diff --git a/builtin/settingtypes.txt b/builtin/settingtypes.txt
index ed7e6c6b1..821762521 100644
--- a/builtin/settingtypes.txt
+++ b/builtin/settingtypes.txt
@@ -1774,7 +1774,7 @@ mgvalleys_cave_width (Cave width) float 0.09
 mgvalleys_dungeon_ymin (Dungeon minimum Y) int -31000
 
 #    Upper Y limit of dungeons.
-mgvalleys_dungeon_ymax (Dungeon maximum Y) int 31000
+mgvalleys_dungeon_ymax (Dungeon maximum Y) int 63
 
 [**Noises]