@@ -1 +1 @@
-UK economy requests for Northern Ireland (`country/ni` in the Public API metadata) now send `country/northern_ireland`, the name .py's UK region registry uses, to the simulation API. The cached result keeps the `country/ni` region. The v2 catalog gives UK constituency and local-authority regions the local-area dataset .py 6.10.0 routes them to (`microcosm_uk_2024_25_dense`) and lists that dataset, instead of the national file, which has no area codes.
+UK economy requests for Northern Ireland (`country/ni` in the Public API metadata) now send `country/northern_ireland`, the name .py's UK region registry uses, to the simulation API. The cached result keeps the `country/ni` region. The v2 catalog gives UK constituency and local-authority regions the local-area dataset .py 6.10.0 routes them to (`microcosm_uk_2024_25_dense`) and lists that dataset, instead of the national file, which has no area codes. The UK metadata now offers Ards and North Down (`N09000011`), the 11th Northern Ireland district, which the local-authority list lacked, so it lists 361 local authorities. The four unitary authorities created in April 2023 (Cumberland, Westmorland and Furness, North Yorkshire and Somerset) now have their own hex positions instead of the shared (0, 0) placeholder. The list's codes, names and positions now match .py 6.10.0's packaged 2023 list.
@@ -58,10 +58,10 @@ E06000059,-1.0,0.0,Dorset
 E06000060,5.0,5.0,Buckinghamshire
 E06000061,9.0,9.0,North Northamptonshire
 E06000062,7.0,6.0,West Northamptonshire
-E06000063,0.0,0.0,Cumberland
-E06000064,0.0,0.0,Westmorland and Furness
-E06000065,0.0,0.0,North Yorkshire
-E06000066,0.0,0.0,Somerset
+E06000063,4.0,18.0,Cumberland
+E06000064,4.0,17.0,Westmorland and Furness
+E06000065,8.0,17.0,North Yorkshire
+E06000066,0.0,1.0,Somerset
 E07000008,12.0,8.0,Cambridge
 E07000009,12.0,9.0,East Cambridgeshire
 E07000010,13.0,10.0,Fenland
@@ -305,6 +305,7 @@ N09000007,-5.0,15.0,Lisburn and Castlereagh
 N09000008,-4.0,18.0,Mid and East Antrim
 N09000009,-5.0,17.0,Mid Ulster
 N09000010,-4.0,15.0,"Newry, Mourne and Down"
+N09000011,-3.0,16.0,Ards and North Down
 S12000005,2.0,24.0,Clackmannanshire
 S12000006,4.0,20.0,Dumfries and Galloway
 S12000008,3.0,20.0,East Ayrshire
 
@@ -5,6 +5,8 @@
 import numpy as np
 import pandas as pd
 import pytest
+from policyengine.countries.uk.regions import build_uk_region_registry
+from policyengine.data.uk_geography_assets import packaged_uk_area_list_path
 from policyengine_core.enums import EnumArray
 from policyengine_core.model_api import Enum
 
@@ -213,12 +215,45 @@ def test__uk_metadata_contains_local_authorities(self, uk_regions):
         ]
         assert len(local_authority_regions) > 0
 
-    def test__uk_has_360_local_authorities(self, uk_regions):
+    def test__uk_has_361_local_authorities(self, uk_regions):
         """Verify the correct number of local authorities are loaded."""
         local_authority_regions = [
             r for r in uk_regions if r.get("type") == "local_authority"
         ]
-        assert len(local_authority_regions) == 360
+        assert len(local_authority_regions) == 361
+
+    def test__ards_and_north_down_is_offered(self, uk_regions):
+        """The 11th Northern Ireland district (N09000011) is a selectable region."""
+        assert {
+            "name": "local_authority/Ards and North Down",
+            "label": "Ards and North Down",
+            "type": "local_authority",
+        } in uk_regions
+
+    def test__every_local_authority_resolves_in_the_policyengine_registry(
+        self, uk_regions
+    ):
+        """Each offered name matches a .py registry label, ignoring case.
+
+        The simulation API resolves ``local_authority/{name}`` to the registry
+        code whose label matches the name, ignoring case.
+        """
+        registry = build_uk_region_registry(
+            include_constituencies=False, include_local_authorities=True
+        )
+        registry_labels = {
+            region.label.casefold(): region.code
+            for region in registry.get_by_type("local_authority")
+        }
+        offered = [
+            region["label"]
+            for region in uk_regions
+            if region.get("type") == "local_authority"
+        ]
+        assert [
+            label for label in offered if label.casefold() not in registry_labels
+        ] == []
+        assert registry_labels["ards and north down"] == "local_authority/N09000011"
 
     def test__local_authority_regions_have_correct_name_format(self, uk_regions):
         """Verify local authority region names have the correct prefix."""
@@ -295,9 +330,44 @@ def test__file_has_correct_columns(self, local_authorities_df):
         expected_columns = {"code", "name", "x", "y"}
         assert expected_columns == set(local_authorities_df.columns)
 
-    def test__file_has_360_local_authorities(self, local_authorities_df):
+    def test__file_has_361_local_authorities(self, local_authorities_df):
         """Verify the correct number of local authorities in file."""
-        assert len(local_authorities_df) == 360
+        assert len(local_authorities_df) == 361
+
+    def test__file_matches_the_installed_policyengine_list(self, local_authorities_df):
+        """Codes, names and hex positions equal .py's packaged 2023 list.
+
+        .py's list is read from the installed package, so a .py update that
+        changes the area frame makes this test fail until the file follows.
+        """
+        policyengine_list = pd.read_csv(packaged_uk_area_list_path("local_authority"))
+
+        def by_code(frame: pd.DataFrame) -> dict[str, tuple[str, float, float]]:
+            return {
+                row.code: (row.name, float(row.x), float(row.y))
+                for row in frame.itertuples(index=False)
+            }
+
+        assert by_code(local_authorities_df) == by_code(policyengine_list)
+
+    def test__april_2023_unitaries_leave_the_origin_placeholder(
+        self, local_authorities_df
+    ):
+        """The four unitaries created in April 2023 have their own hex positions.
+
+        They used to share the (0, 0) placeholder. Another authority may still
+        sit at (0, 0) when .py's list puts it there; the comparison with .py's
+        list above covers every position.
+        """
+        april_2023_unitaries = local_authorities_df[
+            local_authorities_df["code"].isin(
+                ["E06000063", "E06000064", "E06000065", "E06000066"]
+            )
+        ]
+        assert len(april_2023_unitaries) == 4
+        assert not (
+            (april_2023_unitaries["x"] == 0) & (april_2023_unitaries["y"] == 0)
+        ).any()
 
     def test__all_codes_are_valid_ons_codes(self, local_authorities_df):
         """Verify all codes follow ONS local authority code patterns."""
@@ -321,7 +391,7 @@ def test__english_local_authorities_have_e_prefix(self, local_authorities_df):
         english_las = local_authorities_df[
             local_authorities_df["code"].str.startswith("E")
         ]
-        # England has 296 local authorities (majority of the 360 total)
+        # England has 296 local authorities (majority of the 361 total)
         assert len(english_las) == 296
 
     def test__scottish_local_authorities_have_s_prefix(self, local_authorities_df):
@@ -340,6 +410,16 @@ def test__welsh_local_authorities_have_w_prefix(self, local_authorities_df):
         # Wales has 22 principal areas
         assert len(welsh_las) == 22
 
+    def test__northern_irish_local_authorities_have_n_prefix(
+        self, local_authorities_df
+    ):
+        """Verify all 11 Northern Ireland districts have N prefix codes."""
+        northern_irish_las = local_authorities_df[
+            local_authorities_df["code"].str.startswith("N")
+        ]
+        assert len(northern_irish_las) == 11
+        assert "N09000011" in set(northern_irish_las["code"])
+
 
 class TestSimulationCompatibility:
     def test__create_simulation_uses_legacy_tax_benefit_system_signature(self):
Original file line number	Diff line number	Diff line change
`@@ -1 +1 @@`
`1`		-UK economy requests for Northern Ireland (`country/ni` in the Public API metadata) now send `country/northern_ireland`, the name .py's UK region registry uses, to the simulation API. The cached result keeps the `country/ni` region. The v2 catalog gives UK constituency and local-authority regions the local-area dataset .py 6.10.0 routes them to (`microcosm_uk_2024_25_dense`) and lists that dataset, instead of the national file, which has no area codes.
	`1`	+UK economy requests for Northern Ireland (`country/ni` in the Public API metadata) now send `country/northern_ireland`, the name .py's UK region registry uses, to the simulation API. The cached result keeps the `country/ni` region. The v2 catalog gives UK constituency and local-authority regions the local-area dataset .py 6.10.0 routes them to (`microcosm_uk_2024_25_dense`) and lists that dataset, instead of the national file, which has no area codes. The UK metadata now offers Ards and North Down (`N09000011`), the 11th Northern Ireland district, which the local-authority list lacked, so it lists 361 local authorities. The four unitary authorities created in April 2023 (Cumberland, Westmorland and Furness, North Yorkshire and Somerset) now have their own hex positions instead of the shared (0, 0) placeholder. The list's codes, names and positions now match .py 6.10.0's packaged 2023 list.