United States Marshall

The Sheriff of Cochise (1956-1957), renamed U.S. Marshal (1957-1958), was a 58-episode syndicated western-themed crime drama set in Arizona, starring John Bromfield as law enforcement officer Frank Morgan. In the initial season, Morgan was sheriff of Cochise County.

In the second season, Desilu Studios boss Desi Arnaz, Sr., retitled the series so that Morgan would work all over Arizona as a U.S. Marshal and be involved in a greater number of cases.
From: Wikipedia.org

U.S. Marshall opening

U.S. Marshall opening #2