The Watchung Mountains are a group of three long low ridges of volcanic origin, between 400 and 500 feet (120 and 150 m) high, lying parallel to each other in northern New Jersey in the United States. The name is derived from the American Native Lenape name for them, Wach Unks (High Hills).
In the 18th century, the Euro-American settlers also called them the Blue Mountains or Blue Hills (not to be confused with Blue Mountain in Sussex County). The Watchung Mountains are known for their numerous scenic vistas overlooking the skylines of New York City and Newark, New Jersey, as well as their isolated ecosystems containing rare plants, endangered wildlife, rich minerals, and globally imperiled trap rock glade communities.