The Old Mill Road Bridge is a historic bridge near Rocky Ridge, Frederick County, Maryland, United States. The bridge spans Owens Creek southwest of Rocky Ridge on Old Mill Road. It is a Pratt half-hip through truss structure in a single span 69 ft long and 16 ft. It was built in 1882 by the Pittsburgh Bridge Company, Pittsburgh, Pennsylvania. The Old Mill Road Bridge was listed on the National Register of Historic Places in 1979.