Well, there really isn't much to go on so it's anybody's guess. The structures do not look like adobes so it probably isn't too far south, but not necessarily.
I found a site for a Swedish game which has several western game scenarios. Everything is in Swedish, so unless you speak it the scenarios themselves aren't much use but I found lots of town maps, maps of ranches & farms, a stage station, a mission a train car and a riverboat.
http://www.rollspel.com/western/aventyr/w2.htm