diff --git a/src/central/gui/routes.py b/src/central/gui/routes.py
index 73543c1..d548306 100644
--- a/src/central/gui/routes.py
+++ b/src/central/gui/routes.py
@@ -620,6 +620,13 @@ async def adapters_edit_form(
             "SELECT alias FROM config.api_keys ORDER BY alias"
         )
 
+        # Get map tile settings from config.system
+        sys_row = await conn.fetchrow(
+            "SELECT map_tile_url, map_attribution FROM config.system WHERE id = true"
+        )
+        tile_url = sys_row["map_tile_url"] if sys_row else "https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"
+        tile_attribution = sys_row["map_attribution"] if sys_row else "© OpenStreetMap contributors"
+
     settings = row["settings"] or {}
     adapter = {
         "name": row["name"],
@@ -643,6 +650,8 @@ async def adapters_edit_form(
             "api_keys": [{"alias": k["alias"]} for k in api_keys],
             "valid_satellites": _get_valid_satellites(),
             "valid_feeds": sorted(_get_valid_feeds()),
+            "tile_url": tile_url,
+            "tile_attribution": tile_attribution,
         },
     )
     csrf_protect.set_csrf_cookie(signed_token, response)
@@ -749,6 +758,39 @@ async def adapters_edit_submit(
             else:
                 new_settings["feed"] = feed
 
+        # Region validation (applies to all adapters)
+        region_north_str = form.get("region_north", "").strip()
+        region_south_str = form.get("region_south", "").strip()
+        region_east_str = form.get("region_east", "").strip()
+        region_west_str = form.get("region_west", "").strip()
+
+        form_data["region_north"] = region_north_str
+        form_data["region_south"] = region_south_str
+        form_data["region_east"] = region_east_str
+        form_data["region_west"] = region_west_str
+
+        try:
+            region_north = float(region_north_str)
+            region_south = float(region_south_str)
+            region_east = float(region_east_str)
+            region_west = float(region_west_str)
+
+            # Validate latitude bounds
+            if not (-90 <= region_south < region_north <= 90):
+                errors["region"] = "Invalid latitude: south must be less than north, both between -90 and 90"
+            # Validate longitude bounds
+            elif not (-180 <= region_west < region_east <= 180):
+                errors["region"] = "Invalid longitude: west must be less than east, both between -180 and 180"
+            else:
+                new_settings["region"] = {
+                    "north": region_north,
+                    "south": region_south,
+                    "east": region_east,
+                    "west": region_west,
+                }
+        except ValueError:
+            errors["region"] = "Region coordinates must be valid numbers"
+
         # If there are errors, re-render the form
         if errors:
             adapter = {
@@ -764,6 +806,13 @@ async def adapters_edit_submit(
                 "SELECT alias FROM config.api_keys ORDER BY alias"
             )
 
+            # Get map tile settings for re-render
+            sys_row = await conn.fetchrow(
+                "SELECT map_tile_url, map_attribution FROM config.system WHERE id = true"
+            )
+            tile_url = sys_row["map_tile_url"] if sys_row else "https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"
+            tile_attribution = sys_row["map_attribution"] if sys_row else "&copy; OpenStreetMap contributors"
+
             csrf_token, signed_token = csrf_protect.generate_csrf_tokens()
             response = templates.TemplateResponse(
                 request=request,
@@ -777,6 +826,8 @@ async def adapters_edit_submit(
                     "api_keys": [{"alias": k["alias"]} for k in api_keys],
                     "valid_satellites": _get_valid_satellites(),
                     "valid_feeds": sorted(_get_valid_feeds()),
+                    "tile_url": tile_url,
+                    "tile_attribution": tile_attribution,
                 },
                 status_code=200,
             )
diff --git a/src/central/gui/templates/_region_picker.html b/src/central/gui/templates/_region_picker.html
new file mode 100644
index 0000000..5c53bc9
--- /dev/null
+++ b/src/central/gui/templates/_region_picker.html
@@ -0,0 +1,112 @@
+<div id="region-picker-container"
+     data-north="{{ (form_data.region_north if form_data and form_data.region_north else adapter.settings.region.north) if adapter.settings.region else 49.5 }}"
+     data-south="{{ (form_data.region_south if form_data and form_data.region_south else adapter.settings.region.south) if adapter.settings.region else 31.0 }}"
+     data-east="{{ (form_data.region_east if form_data and form_data.region_east else adapter.settings.region.east) if adapter.settings.region else -102.0 }}"
+     data-west="{{ (form_data.region_west if form_data and form_data.region_west else adapter.settings.region.west) if adapter.settings.region else -124.5 }}"
+     data-tile-url="{{ tile_url }}"
+     data-tile-attr="{{ tile_attribution }}">
+
+    <div id="region-map" style="height: 400px; margin-bottom: 1rem;"></div>
+
+    <div class="grid">
+        <div>
+            <label for="region_north">North</label>
+            <input type="number" id="region_north" name="region_north" step="0.0001" min="-90" max="90" readonly
+                   value="{{ (form_data.region_north if form_data and form_data.region_north else adapter.settings.region.north) if adapter.settings.region else 49.5 }}">
+        </div>
+        <div>
+            <label for="region_south">South</label>
+            <input type="number" id="region_south" name="region_south" step="0.0001" min="-90" max="90" readonly
+                   value="{{ (form_data.region_south if form_data and form_data.region_south else adapter.settings.region.south) if adapter.settings.region else 31.0 }}">
+        </div>
+        <div>
+            <label for="region_east">East</label>
+            <input type="number" id="region_east" name="region_east" step="0.0001" min="-180" max="180" readonly
+                   value="{{ (form_data.region_east if form_data and form_data.region_east else adapter.settings.region.east) if adapter.settings.region else -102.0 }}">
+        </div>
+        <div>
+            <label for="region_west">West</label>
+            <input type="number" id="region_west" name="region_west" step="0.0001" min="-180" max="180" readonly
+                   value="{{ (form_data.region_west if form_data and form_data.region_west else adapter.settings.region.west) if adapter.settings.region else -124.5 }}">
+        </div>
+    </div>
+
+    {% if errors and errors.region %}
+    <small style="color: var(--pico-color-red-500);">{{ errors.region }}</small>
+    {% endif %}
+
+    <button type="button" id="region-reset-btn" class="outline secondary">Reset to Saved</button>
+</div>
+
+<script>
+(function() {
+    const container = document.getElementById('region-picker-container');
+    const savedNorth = parseFloat(container.dataset.north);
+    const savedSouth = parseFloat(container.dataset.south);
+    const savedEast = parseFloat(container.dataset.east);
+    const savedWest = parseFloat(container.dataset.west);
+    const tileUrl = container.dataset.tileUrl || 'https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png';
+    const tileAttr = container.dataset.tileAttr || '&copy; OpenStreetMap contributors';
+
+    // Initialize map centered on the bbox
+    const centerLat = (savedNorth + savedSouth) / 2;
+    const centerLng = (savedEast + savedWest) / 2;
+    const map = L.map('region-map').setView([centerLat, centerLng], 5);
+
+    // Add tile layer
+    L.tileLayer(tileUrl, {
+        attribution: tileAttr,
+        maxZoom: 18
+    }).addTo(map);
+
+    // Create initial rectangle
+    const bounds = L.latLngBounds(
+        L.latLng(savedSouth, savedWest),
+        L.latLng(savedNorth, savedEast)
+    );
+
+    // Fit map to bounds
+    map.fitBounds(bounds.pad(0.1));
+
+    // Create editable rectangle
+    const rectangle = L.rectangle(bounds, {
+        color: '#3388ff',
+        weight: 2,
+        fillOpacity: 0.2
+    }).addTo(map);
+
+    // Make rectangle editable
+    rectangle.editing.enable();
+
+    // Input elements
+    const northInput = document.getElementById('region_north');
+    const southInput = document.getElementById('region_south');
+    const eastInput = document.getElementById('region_east');
+    const westInput = document.getElementById('region_west');
+
+    // Update inputs from rectangle bounds
+    function updateInputs() {
+        const b = rectangle.getBounds();
+        northInput.value = b.getNorth().toFixed(4);
+        southInput.value = b.getSouth().toFixed(4);
+        eastInput.value = b.getEast().toFixed(4);
+        westInput.value = b.getWest().toFixed(4);
+    }
+
+    // Listen for rectangle edit events
+    rectangle.on('edit', updateInputs);
+
+    // Reset button
+    document.getElementById('region-reset-btn').addEventListener('click', function() {
+        const originalBounds = L.latLngBounds(
+            L.latLng(savedSouth, savedWest),
+            L.latLng(savedNorth, savedEast)
+        );
+        rectangle.setBounds(originalBounds);
+        updateInputs();
+    });
+
+    // Initial update
+    updateInputs();
+})();
+</script>
diff --git a/src/central/gui/templates/adapters_edit.html b/src/central/gui/templates/adapters_edit.html
index fe7e093..35ae6c8 100644
--- a/src/central/gui/templates/adapters_edit.html
+++ b/src/central/gui/templates/adapters_edit.html
@@ -2,6 +2,13 @@
 
 {% block title %}Central — Edit {{ adapter.name }}{% endblock %}
 
+{% block head %}
+<link rel="stylesheet" href="https://unpkg.com/leaflet@1.9.4/dist/leaflet.css" integrity="sha256-p4NxAoJBhIIN+hmNHrzRCf9tD/miZyoHS5obTRR9BMY=" crossorigin="">
+<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/leaflet.draw/1.0.4/leaflet.draw.css" integrity="sha512-gc3xjCmIy673V6MyOAZhIW93xhM9ei1I+gLbmFjUHIjocENRsLX/QUE1htk5q1XV2D/iie/VQ8DXI6Uj8GB1Og==" crossorigin="anonymous">
+<script src="https://unpkg.com/leaflet@1.9.4/dist/leaflet.js" integrity="sha256-20nQCchB9co0qIjJZRGuk2/Z9VM+kNiyxNV1lvTlZBo=" crossorigin=""></script>
+<script src="https://cdnjs.cloudflare.com/ajax/libs/leaflet.draw/1.0.4/leaflet.draw.js" integrity="sha512-ozq8xQKq6urvuU6jNgkfqAmT7jKN2XumbrX1JiB3TnF7tI48DPI4Ber9dLJ0ikXiRg9G9Vl2jXwqjZ5LDGQ3g==" crossorigin="anonymous"></script>
+{% endblock %}
+
 {% block content %}
 <h1>Edit Adapter: {{ adapter.name }}</h1>
 
@@ -29,18 +36,8 @@
     </fieldset>
 
     <fieldset>
-        <legend>Region (read-only)</legend>
-        {% if adapter.settings.region %}
-        <p>
-            <strong>North:</strong> {{ adapter.settings.region.north }}<br>
-            <strong>South:</strong> {{ adapter.settings.region.south }}<br>
-            <strong>East:</strong> {{ adapter.settings.region.east }}<br>
-            <strong>West:</strong> {{ adapter.settings.region.west }}
-        </p>
-        {% else %}
-        <p>No region configured.</p>
-        {% endif %}
-        <small>Region editing comes in 1b-5.</small>
+        <legend>Region</legend>
+        {% include "_region_picker.html" %}
     </fieldset>
 
     <button type="submit">Save Changes</button>
diff --git a/tests/test_adapters.py b/tests/test_adapters.py
index 2f96e0b..17352f0 100644
--- a/tests/test_adapters.py
+++ b/tests/test_adapters.py
@@ -84,14 +84,17 @@ class TestAdaptersEditForm:
         mock_request.state.operator = MagicMock(id=1, username="testop")
 
         mock_conn = AsyncMock()
-        mock_conn.fetchrow.return_value = {
-            "name": "nws",
-            "enabled": True,
-            "cadence_s": 60,
-            "settings": {"contact_email": "test@example.com", "region": {"north": 49, "south": 24, "east": -66, "west": -125}},
-            "paused_at": None,
-            "updated_at": None,
-        }
+        mock_conn.fetchrow.side_effect = [
+            {
+                "name": "nws",
+                "enabled": True,
+                "cadence_s": 60,
+                "settings": {"contact_email": "test@example.com", "region": {"north": 49, "south": 24, "east": -66, "west": -125}},
+                "paused_at": None,
+                "updated_at": None,
+            },
+            {"map_tile_url": "https://tile.example.com/{z}/{x}/{y}.png", "map_attribution": "Test"},
+        ]
         mock_conn.fetch.return_value = []  # No API keys
 
         mock_pool = MagicMock()
@@ -156,6 +159,10 @@ class TestAdaptersEditSubmit:
         mock_form.get.side_effect = lambda k, d="": {
             "cadence_s": "120",
             "contact_email": "new@example.com",
+            "region_north": "49.0",
+            "region_south": "24.0",
+            "region_east": "-66.0",
+            "region_west": "-125.0",
         }.get(k, d)
         mock_form.getlist.return_value = []
         mock_form.__contains__ = lambda self, k: k == "enabled"
@@ -166,7 +173,7 @@ class TestAdaptersEditSubmit:
             "name": "nws",
             "enabled": True,
             "cadence_s": 60,
-            "settings": {"contact_email": "old@example.com"},
+            "settings": {"contact_email": "old@example.com", "region": {"north": 49, "south": 24, "east": -66, "west": -125}},
             "paused_at": None,
             "updated_at": None,
         }
@@ -200,20 +207,27 @@ class TestAdaptersEditSubmit:
         mock_form.get.side_effect = lambda k, d="": {
             "cadence_s": "30",
             "contact_email": "test@example.com",
+            "region_north": "49.0",
+            "region_south": "24.0",
+            "region_east": "-66.0",
+            "region_west": "-125.0",
         }.get(k, d)
         mock_form.getlist.return_value = []
         mock_form.__contains__ = lambda self, k: k == "enabled"
         mock_request.form = AsyncMock(return_value=mock_form)
 
         mock_conn = AsyncMock()
-        mock_conn.fetchrow.return_value = {
-            "name": "nws",
-            "enabled": True,
-            "cadence_s": 60,
-            "settings": {"contact_email": "test@example.com"},
-            "paused_at": None,
-            "updated_at": None,
-        }
+        mock_conn.fetchrow.side_effect = [
+            {
+                "name": "nws",
+                "enabled": True,
+                "cadence_s": 60,
+                "settings": {"contact_email": "test@example.com", "region": {"north": 49, "south": 24, "east": -66, "west": -125}},
+                "paused_at": None,
+                "updated_at": None,
+            },
+            {"map_tile_url": None, "map_attribution": None},  # system settings for re-render
+        ]
         mock_conn.fetch.return_value = []
 
         mock_pool = MagicMock()
@@ -252,6 +266,10 @@ class TestAdaptersEditSubmit:
         mock_form.get.side_effect = lambda k, d="": {
             "cadence_s": "300",
             "api_key_alias": "nonexistent_key",
+            "region_north": "49.5",
+            "region_south": "31.0",
+            "region_east": "-102.0",
+            "region_west": "-124.5",
         }.get(k, d)
         mock_form.getlist.return_value = ["VIIRS_SNPP_NRT"]
         mock_form.__contains__ = lambda self, k: k == "enabled"
@@ -263,11 +281,12 @@ class TestAdaptersEditSubmit:
                 "name": "firms",
                 "enabled": True,
                 "cadence_s": 300,
-                "settings": {"api_key_alias": "firms", "satellites": ["VIIRS_SNPP_NRT"]},
+                "settings": {"api_key_alias": "firms", "satellites": ["VIIRS_SNPP_NRT"], "region": {"north": 49.5, "south": 31.0, "east": -102.0, "west": -124.5}},
                 "paused_at": None,
                 "updated_at": None,
             },
             None,  # Second call: check api_key exists - returns None
+            {"map_tile_url": None, "map_attribution": None},  # system settings for re-render
         ]
         mock_conn.fetch.return_value = []
 
@@ -306,20 +325,27 @@ class TestAdaptersEditSubmit:
         mock_form.get.side_effect = lambda k, d="": {
             "cadence_s": "120",
             "feed": "invalid_feed",
+            "region_north": "49.0",
+            "region_south": "24.0",
+            "region_east": "-66.0",
+            "region_west": "-125.0",
         }.get(k, d)
         mock_form.getlist.return_value = []
         mock_form.__contains__ = lambda self, k: k == "enabled"
         mock_request.form = AsyncMock(return_value=mock_form)
 
         mock_conn = AsyncMock()
-        mock_conn.fetchrow.return_value = {
-            "name": "usgs_quake",
-            "enabled": True,
-            "cadence_s": 120,
-            "settings": {"feed": "all_hour"},
-            "paused_at": None,
-            "updated_at": None,
-        }
+        mock_conn.fetchrow.side_effect = [
+            {
+                "name": "usgs_quake",
+                "enabled": True,
+                "cadence_s": 120,
+                "settings": {"feed": "all_hour", "region": {"north": 49, "south": 24, "east": -66, "west": -125}},
+                "paused_at": None,
+                "updated_at": None,
+            },
+            {"map_tile_url": None, "map_attribution": None},  # system settings for re-render
+        ]
         mock_conn.fetch.return_value = []
 
         mock_pool = MagicMock()
@@ -360,6 +386,10 @@ class TestAdaptersAudit:
         mock_form.get.side_effect = lambda k, d="": {
             "cadence_s": "120",
             "contact_email": "new@example.com",
+            "region_north": "49.0",
+            "region_south": "24.0",
+            "region_east": "-66.0",
+            "region_west": "-125.0",
         }.get(k, d)
         mock_form.getlist.return_value = []
         mock_form.__contains__ = lambda self, k: k == "enabled"
@@ -370,7 +400,7 @@ class TestAdaptersAudit:
             "name": "nws",
             "enabled": True,
             "cadence_s": 60,
-            "settings": {"contact_email": "old@example.com"},
+            "settings": {"contact_email": "old@example.com", "region": {"north": 49, "south": 24, "east": -66, "west": -125}},
             "paused_at": None,
             "updated_at": None,
         }
@@ -422,6 +452,10 @@ class TestAdaptersJsonbRegression:
         mock_form.get.side_effect = lambda k, d="": {
             "cadence_s": "120",
             "contact_email": "test@example.com",
+            "region_north": "49.0",
+            "region_south": "24.0",
+            "region_east": "-66.0",
+            "region_west": "-125.0",
         }.get(k, d)
         mock_form.getlist.return_value = []
         mock_form.__contains__ = lambda self, k: k == "enabled"
@@ -432,7 +466,7 @@ class TestAdaptersJsonbRegression:
             "name": "nws",
             "enabled": True,
             "cadence_s": 60,
-            "settings": {"contact_email": "old@example.com"},  # dict, as asyncpg returns
+            "settings": {"contact_email": "old@example.com", "region": {"north": 49, "south": 24, "east": -66, "west": -125}},  # dict, as asyncpg returns
             "paused_at": None,
             "updated_at": None,
         }
@@ -471,6 +505,10 @@ class TestAdaptersJsonbRegression:
         mock_form.get.side_effect = lambda k, d="": {
             "cadence_s": "120",
             "contact_email": "new@example.com",
+            "region_north": "49.0",
+            "region_south": "24.0",
+            "region_east": "-66.0",
+            "region_west": "-125.0",
         }.get(k, d)
         mock_form.getlist.return_value = []
         mock_form.__contains__ = lambda self, k: k == "enabled"
@@ -481,7 +519,7 @@ class TestAdaptersJsonbRegression:
             "name": "nws",
             "enabled": True,
             "cadence_s": 60,
-            "settings": {"contact_email": "old@example.com"},  # dict
+            "settings": {"contact_email": "old@example.com", "region": {"north": 49, "south": 24, "east": -66, "west": -125}},  # dict
             "paused_at": None,
             "updated_at": None,
         }
diff --git a/tests/test_region_picker.py b/tests/test_region_picker.py
new file mode 100644
index 0000000..f5a8816
--- /dev/null
+++ b/tests/test_region_picker.py
@@ -0,0 +1,372 @@
+"""Tests for region picker functionality."""
+
+import json
+import os
+from unittest.mock import MagicMock, AsyncMock, patch
+
+import pytest
+
+os.environ.setdefault("CENTRAL_DB_DSN", "postgresql://test:test@localhost/test")
+os.environ.setdefault("CENTRAL_CSRF_SECRET", "testsecret12345678901234567890ab")
+os.environ.setdefault("CENTRAL_NATS_URL", "nats://localhost:4222")
+
+
+class TestRegionPickerInTemplate:
+    """Test region picker is included in adapter edit page."""
+
+    @pytest.mark.asyncio
+    async def test_get_adapters_firms_includes_map_div(self):
+        """GET /adapters/firms includes the map div with tile URL."""
+        from central.gui.routes import adapters_edit_form
+
+        mock_request = MagicMock()
+        mock_request.state.operator = MagicMock(id=1, username="testop")
+
+        mock_conn = AsyncMock()
+        mock_conn.fetchrow.side_effect = [
+            {  # Adapter row
+                "name": "firms",
+                "enabled": True,
+                "cadence_s": 300,
+                "settings": {
+                    "api_key_alias": "firms",
+                    "satellites": ["VIIRS_SNPP_NRT"],
+                    "region": {"north": 49.5, "south": 31.0, "east": -102.0, "west": -124.5}
+                },
+                "paused_at": None,
+                "updated_at": None,
+            },
+            {  # System settings row
+                "map_tile_url": "https://tile.example.com/{z}/{x}/{y}.png",
+                "map_attribution": "Test Attribution",
+            },
+        ]
+        mock_conn.fetch.return_value = [{"alias": "firms"}]
+
+        mock_pool = MagicMock()
+        mock_pool.acquire.return_value.__aenter__ = AsyncMock(return_value=mock_conn)
+        mock_pool.acquire.return_value.__aexit__ = AsyncMock(return_value=None)
+
+        mock_templates = MagicMock()
+        mock_response = MagicMock()
+        mock_templates.TemplateResponse.return_value = mock_response
+
+        mock_csrf = MagicMock()
+        mock_csrf.generate_csrf_tokens.return_value = ("token", "signed")
+        mock_csrf.set_csrf_cookie = MagicMock()
+
+        with patch("central.gui.routes._get_templates", return_value=mock_templates):
+            with patch("central.gui.routes.get_pool", return_value=mock_pool):
+                result = await adapters_edit_form(mock_request, "firms", mock_csrf)
+
+        call_args = mock_templates.TemplateResponse.call_args
+        context = call_args.kwargs.get("context", call_args[1].get("context"))
+
+        # Should include tile URL from config.system
+        assert context["tile_url"] == "https://tile.example.com/{z}/{x}/{y}.png"
+        assert context["tile_attribution"] == "Test Attribution"
+
+
+class TestRegionValidation:
+    """Test region coordinate validation in POST handler."""
+
+    @pytest.mark.asyncio
+    async def test_valid_region_updates_settings(self):
+        """POST with valid bbox updates settings.region."""
+        from central.gui.routes import adapters_edit_submit
+
+        mock_request = MagicMock()
+        mock_request.state.operator = MagicMock(id=1, username="testop")
+
+        mock_form = MagicMock()
+        mock_form.get.side_effect = lambda k, d="": {
+            "cadence_s": "300",
+            "api_key_alias": "firms",
+            "region_north": "45.0",
+            "region_south": "35.0",
+            "region_east": "-100.0",
+            "region_west": "-120.0",
+        }.get(k, d)
+        mock_form.getlist.return_value = ["VIIRS_SNPP_NRT"]
+        mock_form.__contains__ = lambda self, k: k == "enabled"
+        mock_request.form = AsyncMock(return_value=mock_form)
+
+        mock_conn = AsyncMock()
+        mock_conn.fetchrow.side_effect = [
+            {  # Adapter row
+                "name": "firms",
+                "enabled": True,
+                "cadence_s": 300,
+                "settings": {"api_key_alias": "firms", "region": {"north": 49.5, "south": 31.0, "east": -102.0, "west": -124.5}},
+                "paused_at": None,
+                "updated_at": None,
+            },
+            {"id": 1},  # api_key exists check
+        ]
+        mock_conn.execute = AsyncMock()
+
+        mock_pool = MagicMock()
+        mock_pool.acquire.return_value.__aenter__ = AsyncMock(return_value=mock_conn)
+        mock_pool.acquire.return_value.__aexit__ = AsyncMock(return_value=None)
+
+        mock_csrf = MagicMock()
+        mock_csrf.validate_csrf = AsyncMock()
+
+        captured_settings = {}
+
+        async def capture_execute(query, *args):
+            if "UPDATE config.adapters" in query:
+                captured_settings["settings"] = args[2]
+
+        mock_conn.execute.side_effect = capture_execute
+
+        with patch("central.gui.routes.get_pool", return_value=mock_pool):
+            with patch("central.gui.routes.write_audit", new_callable=AsyncMock):
+                result = await adapters_edit_submit(mock_request, "firms", mock_csrf)
+
+        assert result.status_code == 302
+        assert captured_settings["settings"]["region"]["north"] == 45.0
+        assert captured_settings["settings"]["region"]["south"] == 35.0
+        assert captured_settings["settings"]["region"]["east"] == -100.0
+        assert captured_settings["settings"]["region"]["west"] == -120.0
+
+    @pytest.mark.asyncio
+    async def test_north_less_than_south_shows_error(self):
+        """POST with north <= south shows validation error."""
+        from central.gui.routes import adapters_edit_submit
+
+        mock_request = MagicMock()
+        mock_request.state.operator = MagicMock(id=1, username="testop")
+
+        mock_form = MagicMock()
+        mock_form.get.side_effect = lambda k, d="": {
+            "cadence_s": "300",
+            "api_key_alias": "firms",
+            "region_north": "30.0",  # Less than south!
+            "region_south": "35.0",
+            "region_east": "-100.0",
+            "region_west": "-120.0",
+        }.get(k, d)
+        mock_form.getlist.return_value = ["VIIRS_SNPP_NRT"]
+        mock_form.__contains__ = lambda self, k: k == "enabled"
+        mock_request.form = AsyncMock(return_value=mock_form)
+
+        mock_conn = AsyncMock()
+        mock_conn.fetchrow.side_effect = [
+            {
+                "name": "firms",
+                "enabled": True,
+                "cadence_s": 300,
+                "settings": {"api_key_alias": "firms", "region": {"north": 49.5, "south": 31.0, "east": -102.0, "west": -124.5}},
+                "paused_at": None,
+                "updated_at": None,
+            },
+            {"id": 1},  # api_key exists
+            {"map_tile_url": None, "map_attribution": None},  # system settings for re-render
+        ]
+        mock_conn.fetch.return_value = [{"alias": "firms"}]
+
+        mock_pool = MagicMock()
+        mock_pool.acquire.return_value.__aenter__ = AsyncMock(return_value=mock_conn)
+        mock_pool.acquire.return_value.__aexit__ = AsyncMock(return_value=None)
+
+        mock_templates = MagicMock()
+        mock_response = MagicMock()
+        mock_response.status_code = 200
+        mock_templates.TemplateResponse.return_value = mock_response
+
+        mock_csrf = MagicMock()
+        mock_csrf.validate_csrf = AsyncMock()
+        mock_csrf.generate_csrf_tokens.return_value = ("token", "signed")
+        mock_csrf.set_csrf_cookie = MagicMock()
+
+        with patch("central.gui.routes._get_templates", return_value=mock_templates):
+            with patch("central.gui.routes.get_pool", return_value=mock_pool):
+                result = await adapters_edit_submit(mock_request, "firms", mock_csrf)
+
+        call_args = mock_templates.TemplateResponse.call_args
+        context = call_args.kwargs.get("context", call_args[1].get("context"))
+        assert "region" in context["errors"]
+        assert "latitude" in context["errors"]["region"].lower()
+
+    @pytest.mark.asyncio
+    async def test_west_greater_than_east_shows_error(self):
+        """POST with west >= east shows validation error."""
+        from central.gui.routes import adapters_edit_submit
+
+        mock_request = MagicMock()
+        mock_request.state.operator = MagicMock(id=1, username="testop")
+
+        mock_form = MagicMock()
+        mock_form.get.side_effect = lambda k, d="": {
+            "cadence_s": "300",
+            "api_key_alias": "firms",
+            "region_north": "45.0",
+            "region_south": "35.0",
+            "region_east": "-130.0",  # Less than west!
+            "region_west": "-120.0",
+        }.get(k, d)
+        mock_form.getlist.return_value = ["VIIRS_SNPP_NRT"]
+        mock_form.__contains__ = lambda self, k: k == "enabled"
+        mock_request.form = AsyncMock(return_value=mock_form)
+
+        mock_conn = AsyncMock()
+        mock_conn.fetchrow.side_effect = [
+            {
+                "name": "firms",
+                "enabled": True,
+                "cadence_s": 300,
+                "settings": {"api_key_alias": "firms", "region": {"north": 49.5, "south": 31.0, "east": -102.0, "west": -124.5}},
+                "paused_at": None,
+                "updated_at": None,
+            },
+            {"id": 1},
+            {"map_tile_url": None, "map_attribution": None},
+        ]
+        mock_conn.fetch.return_value = [{"alias": "firms"}]
+
+        mock_pool = MagicMock()
+        mock_pool.acquire.return_value.__aenter__ = AsyncMock(return_value=mock_conn)
+        mock_pool.acquire.return_value.__aexit__ = AsyncMock(return_value=None)
+
+        mock_templates = MagicMock()
+        mock_response = MagicMock()
+        mock_response.status_code = 200
+        mock_templates.TemplateResponse.return_value = mock_response
+
+        mock_csrf = MagicMock()
+        mock_csrf.validate_csrf = AsyncMock()
+        mock_csrf.generate_csrf_tokens.return_value = ("token", "signed")
+        mock_csrf.set_csrf_cookie = MagicMock()
+
+        with patch("central.gui.routes._get_templates", return_value=mock_templates):
+            with patch("central.gui.routes.get_pool", return_value=mock_pool):
+                result = await adapters_edit_submit(mock_request, "firms", mock_csrf)
+
+        call_args = mock_templates.TemplateResponse.call_args
+        context = call_args.kwargs.get("context", call_args[1].get("context"))
+        assert "region" in context["errors"]
+        assert "longitude" in context["errors"]["region"].lower()
+
+    @pytest.mark.asyncio
+    async def test_latitude_out_of_bounds_shows_error(self):
+        """POST with lat > 90 shows validation error."""
+        from central.gui.routes import adapters_edit_submit
+
+        mock_request = MagicMock()
+        mock_request.state.operator = MagicMock(id=1, username="testop")
+
+        mock_form = MagicMock()
+        mock_form.get.side_effect = lambda k, d="": {
+            "cadence_s": "300",
+            "api_key_alias": "firms",
+            "region_north": "95.0",  # > 90!
+            "region_south": "35.0",
+            "region_east": "-100.0",
+            "region_west": "-120.0",
+        }.get(k, d)
+        mock_form.getlist.return_value = ["VIIRS_SNPP_NRT"]
+        mock_form.__contains__ = lambda self, k: k == "enabled"
+        mock_request.form = AsyncMock(return_value=mock_form)
+
+        mock_conn = AsyncMock()
+        mock_conn.fetchrow.side_effect = [
+            {
+                "name": "firms",
+                "enabled": True,
+                "cadence_s": 300,
+                "settings": {"api_key_alias": "firms", "region": {"north": 49.5, "south": 31.0, "east": -102.0, "west": -124.5}},
+                "paused_at": None,
+                "updated_at": None,
+            },
+            {"id": 1},
+            {"map_tile_url": None, "map_attribution": None},
+        ]
+        mock_conn.fetch.return_value = [{"alias": "firms"}]
+
+        mock_pool = MagicMock()
+        mock_pool.acquire.return_value.__aenter__ = AsyncMock(return_value=mock_conn)
+        mock_pool.acquire.return_value.__aexit__ = AsyncMock(return_value=None)
+
+        mock_templates = MagicMock()
+        mock_response = MagicMock()
+        mock_response.status_code = 200
+        mock_templates.TemplateResponse.return_value = mock_response
+
+        mock_csrf = MagicMock()
+        mock_csrf.validate_csrf = AsyncMock()
+        mock_csrf.generate_csrf_tokens.return_value = ("token", "signed")
+        mock_csrf.set_csrf_cookie = MagicMock()
+
+        with patch("central.gui.routes._get_templates", return_value=mock_templates):
+            with patch("central.gui.routes.get_pool", return_value=mock_pool):
+                result = await adapters_edit_submit(mock_request, "firms", mock_csrf)
+
+        call_args = mock_templates.TemplateResponse.call_args
+        context = call_args.kwargs.get("context", call_args[1].get("context"))
+        assert "region" in context["errors"]
+
+
+class TestRegionAuditLog:
+    """Test region changes are captured in audit log."""
+
+    @pytest.mark.asyncio
+    async def test_audit_captures_region_change(self):
+        """Audit log captures region change in before/after settings."""
+        from central.gui.routes import adapters_edit_submit
+
+        mock_request = MagicMock()
+        mock_request.state.operator = MagicMock(id=1, username="testop")
+
+        mock_form = MagicMock()
+        mock_form.get.side_effect = lambda k, d="": {
+            "cadence_s": "300",
+            "api_key_alias": "firms",
+            "region_north": "45.0",
+            "region_south": "35.0",
+            "region_east": "-100.0",
+            "region_west": "-120.0",
+        }.get(k, d)
+        mock_form.getlist.return_value = ["VIIRS_SNPP_NRT"]
+        mock_form.__contains__ = lambda self, k: k == "enabled"
+        mock_request.form = AsyncMock(return_value=mock_form)
+
+        mock_conn = AsyncMock()
+        mock_conn.fetchrow.side_effect = [
+            {
+                "name": "firms",
+                "enabled": True,
+                "cadence_s": 300,
+                "settings": {
+                    "api_key_alias": "firms",
+                    "region": {"north": 49.5, "south": 31.0, "east": -102.0, "west": -124.5}
+                },
+                "paused_at": None,
+                "updated_at": None,
+            },
+            {"id": 1},
+        ]
+        mock_conn.execute = AsyncMock()
+
+        mock_pool = MagicMock()
+        mock_pool.acquire.return_value.__aenter__ = AsyncMock(return_value=mock_conn)
+        mock_pool.acquire.return_value.__aexit__ = AsyncMock(return_value=None)
+
+        mock_csrf = MagicMock()
+        mock_csrf.validate_csrf = AsyncMock()
+
+        captured_audit = {}
+
+        async def capture_audit(conn, action, operator_id=None, target=None, before=None, after=None):
+            captured_audit["before"] = before
+            captured_audit["after"] = after
+
+        with patch("central.gui.routes.get_pool", return_value=mock_pool):
+            with patch("central.gui.routes.write_audit", side_effect=capture_audit):
+                result = await adapters_edit_submit(mock_request, "firms", mock_csrf)
+
+        # Before should have old region
+        assert captured_audit["before"]["settings"]["region"]["north"] == 49.5
+        # After should have new region
+        assert captured_audit["after"]["settings"]["region"]["north"] == 45.0
+        assert captured_audit["after"]["settings"]["region"]["south"] == 35.0