Magnum, P.I. is an American crime drama television series starring Tom Selleck as Thomas Magnum, a private investigator (P.I.) living on Oahu, Hawaii. The series ran from December 11, 1980 to May 8, 1988 during its first-run broadcast on the American television network CBS. Magnum, P.I. consistently ranked in the top 20 U.S. television programs in the Nielsen ratings during the first five years of its original run in the United States, finishing as high as number three, that for the 1982–83 season.