The Rossie Velvet Mill Historic District is located in Stonington, Connecticut. Its main focus is the former Rossie Velvet Mill, a large brick industrial facility on the east side of Greenmanville Avenue that is now a research center for the nearby Mystic Seaport Museum. The district extends along Greenmanville Avenue between Pleasant Street in the north and the museum complex in the south. Most of the buildings in the district are residential housing built to house workers at the mill, and were built between about 1850 and 1950. The district includes 51 properties in 120 acres (49 ha).