diff --git a/geodata_pipeline/swe_lods.py b/geodata_pipeline/swe_lods.py
index 3c814ed..9d7991f 100644
--- a/geodata_pipeline/swe_lods.py
+++ b/geodata_pipeline/swe_lods.py
@@ -807,6 +807,7 @@ def _write_boundary_manifest(
         _accumulate_id_stats(sink_stats, sink_ids, lod)
 
         boundary_cells = _boundary_cells_from_ids(boundary_inflow_arr)
+        boundary_sink_cells = _boundary_cells_from_ids(sink_arr)
         source_area_cells = _cell_groups_from_ids(source_area_arr)
         sink_cells = _cell_groups_from_ids(sink_arr)
 
@@ -852,6 +853,7 @@ def _write_boundary_manifest(
                 "boundary_inflow_id_path": boundary_inflow_id_path,
                 "source_area_id_path": source_area_id_path,
                 "boundary_cells": boundary_cells,
+                "boundary_sink_cells": boundary_sink_cells,
                 "source_area_cells": source_area_cells,
                 "sink_cells": sink_cells,
             }