21st Precinct (aka Twenty-First Precinct and Twenty First Precinct) was a police drama broadcast on CBS radio from July 7, 1953, to July 26, 1956. It was initially a summer replacement for My Friend Irma. The program was produced in cooperation with the Patrolmen's Benevolent Association of the City of New York and presented "adaptations from true criminal records in New York...from the policeman's point of view."

Historically, the 21st Pecinct had been located near Gramercy Park in Manhattan but in 1929 the department reorganized the precinct numbering, and the 21st designation was dropped from use. No such precinct existed during the show's run, nor does a 21st exist today. However, the fictional precinct's territory corresponds closely to that of the Upper East Side's 23rd Precinct as it has existed since 1929.[citation needed]Stanley Niss was the producer writer-director. The role of precinct Captain Frank Kennelly was played by Everett Sloane (for the first 109 episodes and briefly in episode 135).

 During episode 109 Captain Frank Kennelly was promoted to Deputy Inspector and reassigned out of the 21st Precinct. He was replaced by Captain Cronin (played by James Gregory, 1955–56) and then Captain Keough (Les Damon, 1956).Other cast regulars were Ken Lynch (as Lt. Matt King), Harold Stone (as Sgt. Waters), Jack Orrison (as Sgt. Collins),[4] and Santos Ortega (as Lt. Gorman).