Hartford's Grist Mill was one of four gristmills along Tomlinson Run, and one of its few surviving artifacts is a 44-inch nether millstone, the stationary lower stone whose carved grooves helped cool the stone and prevent meal or flour from catching fire. The mill site lies in the Wilderness Area of Tomlinson Run State Park, where foundation walls remain one mile downstream of the Old Mill Scout Camping Area and 200 yards below the covered bridge abutments along laurel trail. Joseph and Hannah Coulter built the first mill at this location in 1834. Later owners included John Newell and Thomas Webb, George Baxter Sr., and George Baxter Jr. John B. Hartford rented the mill from 1880 to 1882, bought it in 1882, converted it to steam power, and added a circular sawmill. In 1894 he received a deed for the mill and 37 acres, but he lost it in 1905 for failure to pay taxes, and the mill was later destroyed by flash flood.