The Sanford Mills Historic District is a cohesive collection of historic manufacturing buildings that formerly comprised the main mill yard of the Sanford Mills Company. The seven and a half acre district contains fourteen contributing buildings, two contributing structures, and one non-contributing structure. The contributing resources include eight wood, brick, or concrete mill buildings, two office buildings, a channeled water body with two bridges and several ancillary buildings. The mill yard lies a short distance east of downtown Sanford, and straddles the Mousam River, which powered the textile facilities. The mills were established by Thomas Goodall starting in 1867 and the earliest extant building, the brick Boiler House, dates from approximately 1882. The last mill buildings to be constructed? enormous concrete and metal buildings ? date to circa 1925. The Sanford Mills Historic District possesses integrity of location, design, materials, workmanship, feeling, setting and association. The district was listed in the National Register of Historic Places at the local level of significance and it meets Criterion A for its industrial importance and for its role in the development of the town of Sanford, and Criterion C for its architectural significance. The period of significance commences in 1885, with the construction of the earliest extant buildings, and ends in 1955 when the Burlington Mills Company sold the complex and textile manufacturing in Sanford had largely disappeared.