diff --git a/include/constants/event_objects.h b/include/constants/event_objects.h
index 6b99f19bd..8278c6a66 100644
--- a/include/constants/event_objects.h
+++ b/include/constants/event_objects.h
@@ -241,6 +241,15 @@
 #define OBJ_EVENT_GFX_LUGIA                      237
 #define OBJ_EVENT_GFX_HOOH                       238
 
+// NOTE: By default, the max value for NUM_OBJ_EVENT_GFX is 239.
+//
+// Object event graphics ids are 1 byte in size (max value of 255), and the dynamic
+// graphics ids that start after NUM_OBJ_EVENT_GFX reach this limit. No graphics id
+// uses the value 239 itself, so removing the "+ 1" in OBJ_EVENT_GFX_VARS would
+// allow increasing NUM_OBJ_EVENT_GFX to 240. There are also a handful of unused
+// object graphics that can be removed. If more graphics are needed, anything that
+// stores graphics ids will need to be increased in size. See wiki entry below:
+// https://github.com/pret/pokeemerald/wiki/Feature-Branches#overworld-expansion
 #define NUM_OBJ_EVENT_GFX                        239