Allamuchy is an unincorporated community and census-designated place located within Allamuchy Township, in Warren County, in the U.S. state of New Jersey. As of the 2020 United States census, its population was 208, an increase from the 74 counted in the 2010 census. As of the 2000 United States census, the area of the current CDP was part of the Allamuchy-Panther Valley CDP, which had a 2000 Census population of 3,125.