Upper Greenwood Lake is a census-designated place (CDP) in Passaic and Sussex counties, in the U.S. state of New Jersey. It includes residential neighborhoods around the northern and central parts of its namesake lake. It is primarily in West Milford Township in Passaic County but extends to the northwest into Vernon Township in Sussex County. It is bordered to the west by Wawayanda State Park, to the southeast by Abram S. Hewitt State Forest, and to the northeast by the town of Warwick in Orange County, New York.