Established in 1963, the Southeast Museum offers exhibits on the history of the Town of Southeast, including the early American Circus, the Harlem Line Railroad, the Tilly Foster Mine, the Borden Milk Condensery, and the Croton Reservoir System. In addition, the museum presents various changing exhibits, drawing on its extensive collection of antique farm and household implements, quilts, clothing and assorted Americana reflecting 19th century material culture. The museum is located on Main Street, Brewster in one of Putnam County's largest landmarked buildings, the 1896 Old Town Hall, which is listed in the National Register of Historic Places.

The Southeast Museum is dedicated to collecting, preserving and interpreting the material artifacts and culture significant to the history of the Town of Southeast and its environs.