diff --git a/source/common/filesystem/filesystem.cpp b/source/common/filesystem/filesystem.cpp
index c57b06113..7fd559502 100644
--- a/source/common/filesystem/filesystem.cpp
+++ b/source/common/filesystem/filesystem.cpp
@@ -1446,7 +1446,7 @@ const char *FileSystem::GetResourceFileName (int rfnum) const noexcept
 
 	name = Files[rfnum]->FileName;
 	slash = strrchr (name, '/');
-	return slash != NULL ? slash+1 : name;
+	return (slash != NULL && slash[1] != 0) ? slash+1 : name;
 }
 
 //==========================================================================
diff --git a/source/core/mapinfo.cpp b/source/core/mapinfo.cpp
index ef8ddbd60..25cce2d53 100644
--- a/source/core/mapinfo.cpp
+++ b/source/core/mapinfo.cpp
@@ -55,7 +55,16 @@ CCMD(listmaps)
 {
 	for (unsigned int i = 0; i < numUsedSlots; i++)
 	{
-		Printf("%s - %s\n", mapList[i].fileName.GetChars(), mapList[i].DisplayName());
+		int lump = fileSystem.FindFile(mapList[i].fileName);
+		if (lump >= 0)
+		{
+			int rfnum = fileSystem.GetFileContainer(lump);
+			Printf("%s - %s (%s)\n", mapList[i].fileName.GetChars(), mapList[i].DisplayName(), fileSystem.GetResourceFileName(rfnum));
+		}
+		else
+		{
+			Printf("%s - %s (defined but does not exist)\n", mapList[i].fileName.GetChars(), mapList[i].DisplayName());
+		}
 	}
 }