"[1] 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.

During episode 109, Captain Frank Kennelly was promoted to Deputy Inspector and reassigned out of the 21st Precinct.

Other cast regulars were Ken Lynch (as Lt. Matt King), Harold Stone (as Sgt.

[5] A review in the trade publication Variety called 21st Precinct "an exciting show" and noted that the program essentially imitated Dragnet, "down to the last, authentic, understated detailing of police procedure and the curtain-line explanation: 'Names have been changed to protect the innocent.

'"[5] It added, however, that 21st Precinct offered more insights than Dragnet into a police captain's routine, making the character "seem all the more human".