diff --git a/lib/landclass.py b/lib/landclass.py
index f581994..7760cce 100644
--- a/lib/landclass.py
+++ b/lib/landclass.py
@@ -214,6 +214,9 @@ def lookup_landclass(lat, lon):
                   des_tp, gap_sts, pub_access, category, gis_acres, state_nm
            FROM pad_units
            WHERE ST_Intersects(geom, ST_SetSRID(ST_MakePoint(%s, %s), 4326))
+             -- exclude antimeridian-wrapping polygons: 47 BOEM marine artifacts
+             -- span ~360 deg longitude and false-match non-US points at their lat band
+             AND (ST_XMax(geom) - ST_XMin(geom)) < 60
            ORDER BY gis_acres ASC
            LIMIT 10""",
         (lon, lat)
diff --git a/lib/landclass_test.py b/lib/landclass_test.py
new file mode 100644
index 0000000..cba8ca7
--- /dev/null
+++ b/lib/landclass_test.py
@@ -0,0 +1,44 @@
+#!/usr/bin/env python3
+"""Tests for lib.landclass PAD-US lookups.
+
+Live-PostgreSQL regression test using the skip-if-not-available pattern
+(matching test_real_timezone_db in reverse_bundle_test.py). Plain asserts +
+a __main__ runner, matching the rest of lib/*_test.py.
+
+Note: lookup_landclass swallows DB errors and returns [] (it never raises),
+so PG availability is probed via a known US point (Boise) rather than by
+catching an exception.
+"""
+
+import os
+import sys
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+from lib import landclass
+
+
+def test_landclass_no_antimeridian_false_match():
+    # Yosemite doubles as the liveness probe: a point on real US public land.
+    # (lookup_landclass returns [] when PG is unreachable AND when the point is
+    # off public land, so the probe must be a known-public-land point — e.g.
+    # downtown Boise is private and would yield [] even with PG up.)
+    yosemite = landclass.lookup_landclass(37.85, -119.55)
+    if not yosemite:
+        print("  SKIP: live PG not available (Yosemite returned no rows)")
+        return
+    # Filter must NOT drop legitimate (non-wrapping) US units.
+    assert len(yosemite) >= 1, f"Yosemite should match >=1 PAD-US unit, got {len(yosemite)}"
+
+    # London (51.5074 N) previously false-matched the antimeridian-wrapping
+    # 'Rat Islands' record (ogc_fid 3974, ~360 deg lon span). The < 60 deg
+    # filter must now drop it -> empty result.
+    london = landclass.lookup_landclass(51.5074, -0.1278)
+    assert london == [], f"London should match no PAD-US unit, got {[r.get('unit_name') for r in london]}"
+    print("  PASS: antimeridian filter drops London false-match, keeps Yosemite coverage")
+
+
+if __name__ == '__main__':
+    print("Running landclass tests...")
+    test_landclass_no_antimeridian_false_match()
+    print("All tests passed.")