diff --git a/domain/geospatial/__init__.py b/domain/geospatial/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/domain/geospatial/coordinates.py b/domain/geospatial/coordinates.py
new file mode 100644
index 00000000..a190c23d
--- /dev/null
+++ b/domain/geospatial/coordinates.py
@@ -0,0 +1,15 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True)
+class Coordinates:
+    """A WGS84 point for a Property — longitude/latitude in decimal degrees.
+
+    Resolved from the Ordnance Survey Open-UPRN reference data and fed to the
+    Google Solar fetcher by the Ingestion orchestrator.
+    """
+
+    longitude: float
+    latitude: float
diff --git a/repositories/geospatial/__init__.py b/repositories/geospatial/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/repositories/geospatial/geospatial_repository.py b/repositories/geospatial/geospatial_repository.py
new file mode 100644
index 00000000..558216bb
--- /dev/null
+++ b/repositories/geospatial/geospatial_repository.py
@@ -0,0 +1,17 @@
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+from typing import Optional
+
+from domain.geospatial.coordinates import Coordinates
+
+
+class GeospatialRepository(ABC):
+    """Resolves a Property's coordinates from hosted reference data by UPRN.
+
+    A Repo, not a Fetcher (ADR-0011): it reads stored Ordnance Survey Open-UPRN
+    data, with no live API call. Returns None when the UPRN is not covered.
+    """
+
+    @abstractmethod
+    def coordinates_for(self, uprn: int) -> Optional[Coordinates]: ...
diff --git a/repositories/geospatial/geospatial_s3_repository.py b/repositories/geospatial/geospatial_s3_repository.py
new file mode 100644
index 00000000..c91a57e1
--- /dev/null
+++ b/repositories/geospatial/geospatial_s3_repository.py
@@ -0,0 +1,43 @@
+from __future__ import annotations
+
+from collections.abc import Callable
+from typing import Optional
+
+import pandas as pd
+
+from domain.geospatial.coordinates import Coordinates
+from repositories.geospatial.geospatial_repository import GeospatialRepository
+
+ParquetReader = Callable[[str], pd.DataFrame]
+
+_META_KEY = "spatial/filename_meta.parquet"
+
+
+class GeospatialS3Repository(GeospatialRepository):
+    """Reads the partitioned Ordnance Survey Open-UPRN parquet dataset.
+
+    `spatial/filename_meta.parquet` maps a UPRN range (lower/upper) to a
+    partition file; that partition carries `UPRN`/`LATITUDE`/`LONGITUDE`. The
+    parquet reader is injected so the dataset can be sourced from S3 in
+    production or a fixture directory in tests — the Repo holds no S3/HTTP code.
+    """
+
+    def __init__(self, read_parquet: ParquetReader) -> None:
+        self._read_parquet = read_parquet
+
+    def coordinates_for(self, uprn: int) -> Optional[Coordinates]:
+        meta = self._read_parquet(_META_KEY)
+        covering = meta[(meta["lower"] <= uprn) & (meta["upper"] >= uprn)]
+        if covering.empty:
+            return None
+        filename = str(covering["filenames"].iloc[0])
+
+        partition = self._read_parquet(f"spatial/{filename}")
+        rows = partition[partition["UPRN"] == uprn]
+        if rows.empty:
+            return None
+        row = rows.iloc[0]
+        return Coordinates(
+            longitude=float(row["LONGITUDE"]),
+            latitude=float(row["LATITUDE"]),
+        )
diff --git a/tests/repositories/geospatial/__init__.py b/tests/repositories/geospatial/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/tests/repositories/geospatial/test_geospatial_repository.py b/tests/repositories/geospatial/test_geospatial_repository.py
new file mode 100644
index 00000000..4b0834c9
--- /dev/null
+++ b/tests/repositories/geospatial/test_geospatial_repository.py
@@ -0,0 +1,71 @@
+"""GeospatialRepo resolves a Property's coordinates from the OS Open-UPRN data.
+
+A reference-data lookup, not a Fetcher (ADR-0011): no live OS API call. The
+adapter reads the partitioned Open-UPRN parquet via an injected reader, so the
+test exercises the partition lookup + filter against real fixture parquets with
+no network.
+"""
+
+from __future__ import annotations
+
+from collections.abc import Callable
+from pathlib import Path
+
+import pandas as pd
+
+from domain.geospatial.coordinates import Coordinates
+from repositories.geospatial.geospatial_s3_repository import GeospatialS3Repository
+
+
+def _reader(base: Path) -> Callable[[str], pd.DataFrame]:
+    def read(key: str) -> pd.DataFrame:
+        return pd.read_parquet(base / key)
+
+    return read
+
+
+def _write_open_uprn(base: Path) -> None:
+    spatial = base / "spatial"
+    spatial.mkdir(parents=True, exist_ok=True)
+    pd.DataFrame(
+        {"lower": [0], "upper": [100000], "filenames": ["0_100000.parquet"]}
+    ).to_parquet(spatial / "filename_meta.parquet")
+    pd.DataFrame(
+        {
+            "UPRN": [12345, 12346],
+            "LATITUDE": [51.5074, 51.6000],
+            "LONGITUDE": [-0.1278, -0.2000],
+        }
+    ).to_parquet(spatial / "0_100000.parquet")
+
+
+def test_coordinates_for_returns_lon_lat(tmp_path: Path) -> None:
+    # Arrange
+    _write_open_uprn(tmp_path)
+    repo = GeospatialS3Repository(_reader(tmp_path))
+
+    # Act
+    coords = repo.coordinates_for(12345)
+
+    # Assert
+    assert coords == Coordinates(longitude=-0.1278, latitude=51.5074)
+
+
+def test_coordinates_for_returns_none_when_uprn_absent(tmp_path: Path) -> None:
+    # Arrange
+    _write_open_uprn(tmp_path)
+    repo = GeospatialS3Repository(_reader(tmp_path))
+
+    # Act / Assert — uprn inside the partition range but not present in the data
+    assert repo.coordinates_for(99999) is None
+
+
+def test_coordinates_for_returns_none_when_no_partition_covers_uprn(
+    tmp_path: Path,
+) -> None:
+    # Arrange
+    _write_open_uprn(tmp_path)
+    repo = GeospatialS3Repository(_reader(tmp_path))
+
+    # Act / Assert — uprn beyond every partition's range
+    assert repo.coordinates_for(500000) is None