Cooper Gristmill is 1 mi. w. of jct. US 206 at 66 Washington Tpke., in Black River Park. The site's original mill was used for grinding flour in the late 1700s; the present structure was built in 1826 by Nathan Cooper. Interpreters in period attire explain the mill's history and the working mill stones that once produced 1,600 pounds of wheat flour and corn meal an hour.