21 Beacon Street is an American detective television series that originally aired on NBC from July 2 to September 10, 1959.

Produced by Filmways,[1] the summer replacement series for The Tennessee Ernie Ford Show[2]: 146  consisted of 11 black-and-white 30-minute episodes.

[4] Dennis Chase was a private investigator with an office on 21 Beacon Street, in an unspecified city.

[5] Chase and his assistants worked to discover who the criminals were, but then notified the police to come and apprehend the law breakers.

Bruce Geller claimed never to have seen the earlier show; Beacon Street's story editor and pilot scripter, Laurence Heath, would later write several episodes of Mission: Impossible.