The show is set in San Antonio, Texas but actually filmed in central New Mexico: Albuquerque, Los Lunas, Belen, and the surrounding areas of Bernalillo and Valencia County.
Brendan Fehr (Dr. Drew Alister) and recurring guest star Adam Rodriguez (Dr. Joey Chavez) worked together previously on Roswell (1999) and CSI: Miami (2002).
TC Callahan is Irish on the show, claiming that he and his family moved to America when he was 10. Eoin Macken, the actor who places him, is actually Irish: born and raised in Dublin.
Every scene that has a Texas Flag hanging flat on the wall is presenting it backwards: Texas Law states that when the flag is hung downward, the white stripe must be on the left.
Was not picked up for a 5th season by NBC. Cancelled