Jack's Mountain Covered Bridge, Circa 1890 at 75 feet long. The Jacks Mountain Covered Bridge is a historic covered bridge in Hamiltonban Township, Adams County, Pennsylvania. It was built in 1890, and is a 75-foot-long, Burr truss bridge with narrow horizontal siding and a tin covered gable roof. The bridge crosses Tom's Creek. This is the only bridge in Adams County that is opened to vehicular traffic, this bridge has red lights at each end. read more