Lebanon is a borough in Hunterdon County, in the U.S. state of New Jersey. As of the 2020 United States census, the borough's population was 1,665, the highest ever in any decennial census and an increase of 307 (+22.6%) from the 2010 census count of 1,358, which in turn reflected an increase of 293 (+27.5%) from the 1,065 counted in the 2000 census.