Long Valley is an unincorporated community and census-designated place (CDP) in Washington Township, Morris County, New Jersey, in the United States. Once known as German Valley from its foundation during the colonial era, the community was renamed in response to anti-German sentiment during World War I. As of the 2020 census, the CDP's population was 1,827.
Geography
Long Valley is in southwestern Morris County, in the center of Washington Township. The village of Long Valley is at the center of the CDP, within the valley of the South Branch of the Raritan River. The CDP extends northwest up onto Schooleys Mountain, rising above the valley, where it includes the community of Springtown. To the southeast the CDP includes the lower Fox Hill Range, which rises above the valley. Chester is to the east via East Mill Road (CR 513), while Hackettstown is to the north via Schooley's Mountain Road (CR 517).
According to the U.S. Census Bureau, the CDP has a total area of , including of land and of water (1.24%).