Fort Abandon is a rundown New California Republic fort located in an unknown area of the American southwest. The railway has a crossroads here. It was originally called Fort Aradesh, and was a major fortification. However, Caesar's Legion attempted to destroy NCR's presence in the east, and actually succeeded in destroying the fort. The name changed after NCR's control of the frontier receded.
Fort Abandon is mentioned by Ulysses in the Fallout: New Vegas add-on Lonesome Road. He initially calls it "Fort Aradesh," then corrects himself, calling it "Fort Abandon."