diff --git a/overviewer_core/world.py b/overviewer_core/world.py
index af0f240..07c7b90 100644
--- a/overviewer_core/world.py
+++ b/overviewer_core/world.py
@@ -255,11 +255,11 @@ class RegionSet(object):
         this regionset.  Either "nether", "end" or "overworld"
         """
         # path will be normalized in __init__
-        if self.regiondir.endswith("/DIM-1/region"): 
+        if self.regiondir.endswith(os.path.normpath("/DIM-1/region")):
             return "nether"
-        elif self.regiondir.endswith("/DIM1/region"):
+        elif self.regiondir.endswith(os.path.normpath("/DIM1/region")):
             return "end"
-        elif self.regiondir.endswith("/region"):
+        elif self.regiondir.endswith(os.path.normpath("/region")):
             return "overworld"
         else:
             raise Exception("Woah, what kind of dimension is this! %r" % self.regiondir)