Riverside Woolen Mill, known by various names including the Walker Mill, the Maple Grove Mill, and the Sebasticook Woolen Mill, was built in 1884 by Dennison Walker and sat amongst a maple grove along the Sebasticook River in Pittsfield, Maine. Under ownership of Fred Smith, it became the first mill in the state to sell clothing directly to the public when Smith opened the Riverside Woolen Co. store on the site in 1907. The mill was sold to the American Woolen Company in 1914 and closed in 1934. It burned to the ground in 1997.

The caption reads, "Sebasticook Woolen Mill, Pittsfield, Maine."

The Tichnor Brothers printing company published this type of postcard circa 1938.