Located in a namesake town in Pennsylvania where it was based, the Fleetwood Body Corporation was founded in 1910. It began as a small community of craftsmen founded by Henry Fleetwood, Esq. of Penwortham, near Lancaster, England. Rich traditions of 300 years of coach-building that the Fleetwood Body Company applied to its work secured for the company a high reputation in automobile circles around the world, beginning in the twenties. Bespoke coachwork was built there for Cadillac automobiles up to 1930. Starting in 1925 Fleetwood bodies were reserved exclusively for Cadillac cars since they were bought out by General Motors in September of that year. The "Fleetwood" name was used from 1965 to designate a group or series of Cadillac models at the top of the price range.
The original plant at Fleetwood was closed on January 1st, 1931 and moved to Cadillac Plant 18 in Detroit. The plant last completed several replicas of Napoleon's Coronation Coach, well-known symbol of the Fisher Body Corporation.
Sources
http://www.car-nection.com/yann/dbas_txt/indx2001.htm