diff --git a/src/mkroom.c b/src/mkroom.c
index 0a3319289..d5196ce1a 100644
--- a/src/mkroom.c
+++ b/src/mkroom.c
@@ -652,6 +652,11 @@ inside_room(croom, x, y)
 struct mkroom *croom;
 xchar x, y;
 {
+    if (croom->irregular) {
+        int i = (int) ((croom - g.rooms) + ROOMOFFSET);
+        return (!levl[x][y].edge && (int) levl[x][y].roomno == i);
+    }
+
     return (boolean) (x >= croom->lx - 1 && x <= croom->hx + 1
                       && y >= croom->ly - 1 && y <= croom->hy + 1);
 }
diff --git a/src/sp_lev.c b/src/sp_lev.c
index f5078c7d4..d60c4a062 100755
--- a/src/sp_lev.c
+++ b/src/sp_lev.c
@@ -1794,6 +1794,9 @@ struct mkroom *croom;
     if (MON_AT(x, y) && enexto(&cc, x, y, pm))
         x = cc.x, y = cc.y;
 
+    if (croom && !inside_room(croom, x, y))
+        return;
+
     if (m->align != AM_SPLEV_RANDOM)
         mtmp = mk_roamer(pm, Amask2align(amask), x, y, m->peaceful);
     else if (PM_ARCHEOLOGIST <= m->id && m->id <= PM_WIZARD)