Located at the confluence of McKinstry Brook and the Quinebaug River in central Southbridge, Massachusetts, the complex consists of a cluster of mill buildings and a rare collection of 1830s brick mill worker housing units located nearby.

[2] Among the buildings erected in 1836 are the Big Mill, a five-story brick structure that is the dominant feature of the complex.

Extensively modified in 1850, the most distinctive feature of this building is an end stairwell which is capped by a tower with a Romanesque belfry.

[2] In the second half of the 19th century Hamilton was the dominant employer in Southbridge, producing primarily woolen products, especially after the American Civil War cut off cotton supplies.

It remained a major presence in town, although it had been eclipsed in size by the American Optical Company, until a strike in 1934 closed its doors forever.