Harlingen is a census-designated place (CDP) and unincorporated area located within Montgomery Township, in Somerset County, New Jersey, United States. As of the 2010 United States Census, the CDP's population was 297. It is adjacent to the historical areas of Dutchtown, New Jersey and Bridgepoint, New Jersey. Harlingen Road and U.S. Route 206, are in Harlingen. The Harlingen Dutch Reformed Church on Route 206 is extant and had an associated cemetery. The town was a stop on the short-lived Mercer and Somerset Railway.