Long Valley is an unincorporated community and census-designated place (CDP) located within Washington Township, in Morris County, in the U.S. state of New Jersey. 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 2010 United States Census, the CDP's population was 1,879.

Washington Township is a township in southwestern Morris County, in the U.S. state of New Jersey. As of the 2020 United States census, the township's population was 18,197, a decrease of 336 (−1.8%) from the 2010 census count of 18,533, which in turn reflected an increase of 941 (+5.3%) from the 17,592 counted in the 2000 census.