Fort Buchanan was a US Army post founded in 1856 three miles southwest of present-day Sonoita in Santa Cruz County, Arizona, on the east slope of what is now called Hog Canyon. At the time, the area was under constant threat from hostile Apaches. Full-scale war with the local Chiricahua Apache was initiated by the Bascom affair in early 1861, during which Lieutenant George Nicholas Bascom and his patrol were based at Fort Buchanan.