Rumsey Hall School is a coeducational boarding and country day school for kindergarten through ninth grade located in Washington, Connecticut. As of 2005, the school enrolls approximately 300 students and employs 54 full- and part-time faculty members. Thomas W. Farmen, the school's fifth headmaster, was appointed in 1985. The school grounds comprise 30 buildings on 148 acres (0.60 km2) along the Bantam River.
Founded in 1900 by Lillias Rumsey Sanford (1850–1940) as an all-boys school in Seneca Falls, New York, Rumsey Hall School moved to Cornwall, Connecticut in 1906 and then to its current location in 1949, at which point it became coeducational. In 1956 Marvelwood School was founded in Cornwall, taking over the main building previously occupied by Rumsey Hall, but preserving the name. When Marvelwood moved in 1995 to Kent, Connecticut, the Rumsey Hall building fell into disrepair.