The western fort set used on the series was in Kanab, UT, and was originally built for the western Pony Express (1953). It was also seen in the opening credits of TV's Branded (1965) and was featured extensively in Duel at Diablo (1966).
The unit depicted in the series, the 5th Cavalry, was an actual regiment in the US army. It fought in the Mexican War and the US Civil War and afterwards served in the Indian campaigns in Nebraska and Kansas. Among its members were future Confederate General Robert E. Lee (who was a lieutenant colonel at the time) and Buffalo Bill Cody, better known as "Buffalo Bill Cody", who served as a scout.
The series title, "Boots and Saddles", refers to a bugle call sounded for cavalry to mount their horses and get in formation. It was adopted by the United States Army in the 1840s.