Constructed between 1810 and 1820, the imposing brick structure that is Colvin Run Mill in Fairfax County is a survivor of the hundreds of early gristmills that once dotted Virginia’s countryside, enterprises essential to the state’s agricultural economy. With its exterior overshot wheel, Colvin Run Mill offers a picture-book image of this rural architectural form. Its first owner and miller was most likely Philip Carper, who held the property from 1811 until 1842. The mill remained in operation through the 1930s. The realignment of the adjacent Route 7, however, disrupted the water supply, and the mill fell into disuse and disrepair. By the time the Fairfax County Park Authority purchased it in 1965, the mill was approaching ruinous condition. Painstakingly restored, with its machinery patterned after the principles of the 19th-century mill engineer Oliver Evans, Colvin Run Mill was opened as a museum of early milling design and practices.