Robert Sparr was originally set to direct, but he was killed in a plane crash while scouting locations in Colorado. Gordon Douglas was hired to replace him.
Three of the principal actors--Warren Oates, Mariette Hartley and John Davis Chandler--also starred in Sam Peckinpah's Ride the High Country (1962).
The movie's poster shows Lee Van Cleef wearing the hat that is only worn by Warren Oates. At no point in the movie does this happen.
Lee Van Cleef's first American-made movie since 1962's "How The West Is Won".
Also - his first lead/starring role in one.
Last screen appearance of Marie Gomez as of 08 JA 2023.