diff --git a/src/lib/entitySubmissionHelpers.ts b/src/lib/entitySubmissionHelpers.ts
index 21e058a2..0d3b2d4e 100644
--- a/src/lib/entitySubmissionHelpers.ts
+++ b/src/lib/entitySubmissionHelpers.ts
@@ -975,7 +975,7 @@ export async function submitTimelineEvent(
     .from('submission_items')
     .insert({
       submission_id: submission.id,
-      item_type: 'timeline_event',
+      item_type: 'milestone',
       action_type: 'create',
       item_data: itemData as unknown as Json,
       status: 'pending',
@@ -1064,7 +1064,7 @@ export async function submitTimelineEventUpdate(
     .from('submission_items')
     .insert({
       submission_id: submission.id,
-      item_type: 'timeline_event',
+      item_type: 'milestone',
       action_type: 'edit',
       item_data: itemData as unknown as Json,
       original_data: originalEvent as unknown as Json,
diff --git a/supabase/migrations/20251015200347_e221c145-f138-45a9-9305-4eba5a973250.sql b/supabase/migrations/20251015200347_e221c145-f138-45a9-9305-4eba5a973250.sql
new file mode 100644
index 00000000..5361105e
--- /dev/null
+++ b/supabase/migrations/20251015200347_e221c145-f138-45a9-9305-4eba5a973250.sql
@@ -0,0 +1,23 @@
+-- Add 'milestone' to submission_items item_type constraint
+ALTER TABLE public.submission_items 
+DROP CONSTRAINT IF EXISTS submission_items_item_type_check;
+
+ALTER TABLE public.submission_items 
+ADD CONSTRAINT submission_items_item_type_check 
+CHECK (item_type IN (
+  'park',
+  'ride',
+  'review',
+  'photo',
+  'ride_model',
+  'manufacturer',
+  'operator',
+  'designer',
+  'property_owner',
+  'photo_edit',
+  'photo_delete',
+  'milestone'
+));
+
+COMMENT ON CONSTRAINT submission_items_item_type_check ON public.submission_items IS 
+'milestone items represent timeline/historical events for entities';
\ No newline at end of file