diff --git a/internal/repository/postgres/dataset.go b/internal/repository/postgres/dataset.go
index 23e64b9..de51ca3 100644
--- a/internal/repository/postgres/dataset.go
+++ b/internal/repository/postgres/dataset.go
@@ -166,11 +166,22 @@ func (r *DatasetRepository) SetProperties(ctx context.Context, id uuid.UUID, pro
 	return nil
 }
 
-// MarkReady sets the dataset status to ready and clears any error.
-func (r *DatasetRepository) MarkReady(ctx context.Context, id uuid.UUID) error {
+// MarkReady sets the dataset status to ready, stores the dissolved feature
+// geometry (GeoJSON in EPSG:4326; nil keeps the existing geometry, reduced to
+// the union of all features via ST_UnaryUnion), and clears any error.
+func (r *DatasetRepository) MarkReady(ctx context.Context, id uuid.UUID, geometry []byte) error {
+	var geom any // nil -> SQL NULL -> CASE keeps existing geometry
+	if len(geometry) > 0 {
+		geom = string(geometry)
+	}
 	tag, err := r.pool.Exec(ctx,
-		`UPDATE datasets SET status = $2, parse_error = NULL, updated_at = now() WHERE id = $1`,
-		id, domain.DatasetStatusReady,
+		`UPDATE datasets
+		 SET status = $2,
+		     geometry = CASE WHEN $3::text IS NULL THEN geometry
+		                     ELSE ST_UnaryUnion(ST_SetSRID(ST_GeomFromGeoJSON($3), 4326)) END,
+		     parse_error = NULL, updated_at = now()
+		 WHERE id = $1`,
+		id, domain.DatasetStatusReady, geom,
 	)
 	if err != nil {
 		return mapError(err)
diff --git a/internal/service/dataset.go b/internal/service/dataset.go
index a6ee1fb..2f96cf7 100644
--- a/internal/service/dataset.go
+++ b/internal/service/dataset.go
@@ -31,7 +31,7 @@ type DatasetRepository interface {
 	Delete(ctx context.Context, id uuid.UUID) error
 	MarkParsed(ctx context.Context, id uuid.UUID, cols []domain.AttributeColumn) error
 	MarkParseFailed(ctx context.Context, id uuid.UUID, reason string) error
-	MarkReady(ctx context.Context, id uuid.UUID) error
+	MarkReady(ctx context.Context, id uuid.UUID, geometry []byte) error
 	MarkConverted(ctx context.Context, id uuid.UUID, cogKey string, footprint []byte) error
 	SetProperties(ctx context.Context, id uuid.UUID, properties, geometry []byte) error
 	SaveMapping(ctx context.Context, id uuid.UUID, katoColumn string, years []domain.YearColumn) (domain.Dataset, error)
@@ -515,9 +515,11 @@ func (s *DatasetService) SaveMapping(ctx context.Context, id uuid.UUID, in Mappi
 }
 
 // Extract reads a mapped dataset's file, unpivots its attribute table into
-// observations keyed by KATO code and date, and marks the dataset ready. It is
-// invoked by the worker. Permanent failures (unparsable file) are recorded;
-// transient failures (storage/DB) are returned for retry.
+// observations keyed by KATO code and date, records the dissolved feature
+// geometry, and marks the dataset ready. It is invoked by the worker. Permanent
+// failures (unparsable file) are recorded; transient failures (storage/DB) are
+// returned for retry. Geometry extraction is best-effort: a failure leaves
+// geometry unset rather than failing the job.
 func (s *DatasetService) Extract(ctx context.Context, id uuid.UUID) error {
 	dataset, err := s.repo.GetByID(ctx, id)
 	if err != nil {
@@ -541,7 +543,9 @@ func (s *DatasetService) Extract(ctx context.Context, id uuid.UUID) error {
 	if err := s.repo.ReplaceObservations(ctx, id, obs); err != nil {
 		return err // transient
 	}
-	return s.repo.MarkReady(ctx, id)
+
+	geometry := s.vectorGeometry(ctx, dataset.Filename, data)
+	return s.repo.MarkReady(ctx, id, geometry)
 }
 
 // buildObservations unpivots rows into observations. Rows without a KATO code
diff --git a/internal/service/dataset_test.go b/internal/service/dataset_test.go
index 547d601..7bb83fb 100644
--- a/internal/service/dataset_test.go
+++ b/internal/service/dataset_test.go
@@ -101,11 +101,14 @@ func (r *stubDatasetRepo) SaveMapping(_ context.Context, id uuid.UUID, kato stri
 	return d, nil
 }
 
-func (r *stubDatasetRepo) MarkReady(_ context.Context, id uuid.UUID) error {
+func (r *stubDatasetRepo) MarkReady(_ context.Context, id uuid.UUID, geometry []byte) error {
 	d, ok := r.store[id]
 	if !ok {
 		return domain.ErrNotFound
 	}
+	if len(geometry) > 0 {
+		d.Geometry = geometry
+	}
 	d.Status = domain.DatasetStatusReady
 	r.store[id] = d
 	return nil
@@ -765,7 +768,9 @@ func TestDatasetService_Extract(t *testing.T) {
 	}
 	rows := []map[string]string{{"като": "751010000", "F_2023": "100"}}
 	rp := RowParser(func(string, []byte) ([]map[string]string, error) { return rows, nil })
-	svc := NewDatasetService(repo, &stubStore{}, stubCategoryReader{exists: true}, &stubEnqueuer{}, noopParser, rp, &stubConverter{})
+	geom := []byte(`{"type":"GeometryCollection","geometries":[]}`)
+	conv := &stubConverter{vectorGeom: geom}
+	svc := NewDatasetService(repo, &stubStore{}, stubCategoryReader{exists: true}, &stubEnqueuer{}, noopParser, rp, conv)
 
 	if err := svc.Extract(context.Background(), id); err != nil {
 		t.Fatalf("unexpected error: %v", err)
@@ -773,6 +778,9 @@ func TestDatasetService_Extract(t *testing.T) {
 	if repo.store[id].Status != domain.DatasetStatusReady {
 		t.Fatalf("want ready, got %q", repo.store[id].Status)
 	}
+	if string(repo.store[id].Geometry) != string(geom) {
+		t.Fatalf("want geometry %s, got %s", geom, repo.store[id].Geometry)
+	}
 	got := repo.observations[id]
 	if len(got) != 1 || got[0].KatoCode != "751010000" || got[0].Value == nil || *got[0].Value != 100 {
 		t.Fatalf("unexpected observations: %+v", got)