From Wikipedia:
A television series spun off from the film, starring Gregory Harrison as Logan 5 and Heather Menzies as Jessica 6, lasted one season of 14 episodes, from September 16, 1977 through January 7, 1978 on U.S. television (CBS-TV). D. C. Fontana served as story editor and employed several other writers from Star Trek as well as the original novel's authors. The series was produced by Ivan Goff.
To save money, the series depicted Logan and Jessica — still pursued by Francis (Randolph Powell) — travelling in a futuristic hovercraft-like vehicle on a cross-country trek to Sanctuary in a post-apocalyptic America. The domed city was seen only in the pilot and two other episodes, using recycled footage from the film. In a change from the book and film, the television series had the city run by a cabal of elderly citizens; Francis has been promised a life beyond thirty as a city elder if he can bring back the fugitives. Logan and Jessica were joined by an android, REM, played for comic relief by Donald Moffat. Most of the plots were conventional genre clichés, including one "Logan-has-amnesia" episode.