Greenwood Lake is an interstate lake approximately seven miles (11 km) long, straddling the border of New York and New Jersey. It is located in the Town of Warwick and the Village of Greenwood Lake, New York (in Orange County) and West Milford, New Jersey (in Passaic County). It is the source of the Wanaque River. The lake was originally called "Quampium" by the Munsee Native Americans who lived there. It was renamed "Long Pond" by Europeans, who settled the area in the 18th century for farming and ironmaking, and eventually came to be re-christened "Greenwood Lake."