I found this map on an amazing website called the David Rumsey Historical Map Collection. The site link is here: link. (I suggest registering at the web site and then using the link on the right hand side to go to the “Luna browser” where you can export some high resolution maps to use in your game campaigns). The link to the very high resolution map is here:
The website is a great resource for old west games since it has maps for every western state and for about every decade of the 1800’s. This map in particular has dozens of Army forts highlighted in blue on an already detailed map of Arizona and New Mexico. This was probably a reflection of the Civil War spilling over into the western territories. In the latter decades of the 1800’s many of these forts were demilitarized and fell into disuse. If you ever played the video game called Red Dead Redemption you might recall Fort Mercer as an example of an old Army fort taken over by bandits and outlaws.