When McCloud goes to Mexico to look for Robert Devlin he does not go any further than the Mexican Village set on the Universal back lot which had given service to many of Universal's westerns like 'The Virginian' and Alias Smith and Jones'.
The picture on the wall in Chief Peter B. Clifford's office is that of then New York City Mayor John Lindsay.
Even though Sgt Broadhurst has no part in this story, he can still be seen in the background when Devlin is at the police station. Either that, or it may have been Terry Carter's stunt double.
When Mastin takes the surprise call from Robert Devlin, he is watching the film The Black Cat on television. The film starred Boris Karloff and Bela Lugosi.
The large painting that Martin emerges from was done by Thomas J. Wright, who did all of the paintings used for the TV series Night Gallery (1969).