County House Mountain in Warren County, New Jersey, rises to 1,142 feet at its main peak in Mansfield Township and forms part of the New York–New Jersey Highlands, a northeastern section of the Appalachian Mountains. Separated from Oxford Mountain by Sykes Gap and divided by Stewart Gap, it is more than a modest local summit. The mountain also marks part of the watershed divide between Pohatcong Creek and the Pequest River, giving it geographic significance within the region.