McKinstry's Mills Historic District

The McKinstry's Mills Historic District is a national historic district in Union Bridge, located in Carroll and Frederick County, Maryland. The district comprises the entirety of the settlement of McKinstry's Mills, a 26 acre hamlet consisting of six separate properties that were owned and developed in the 19th century by the McKinstry family, local millers. At the center is a $3 1/2$-story grist mill constructed in 1844. Also included are the McKinstry homestead, built between 1825 and 1835; the residence of miller Samuel McKinstry, dated 1849; a store building of 1850; and two other small houses and a variety of outbuildings. There is also a 1908 Warren pony truss bridge.

It was added to the National Register of Historic Places in 1997.