Montague Township is a township in Sussex County, New Jersey, United States, in the New York City Metropolitan Area. As of the 2010 United States Census, the township's population was 3,847, reflecting an increase of 435 (+12.7%) from the 3,412 counted in the 2000 Census, which had in turn increased by 580 (+20.5%) from the 2,832 counted in the 1990 Census. High Point, within Montague Township, is the highest elevation within New Jersey at an altitude of above sea level. Montague is also the northernmost municipality in the state of New Jersey.