Watchung Reservation is the largest park in Union County, New Jersey, United States. It is bounded by the city of Summit, the borough of Mountainside, and the townships of Berkeley Heights, Scotch Plains, and Springfield. The reservation consists mainly of the upper valley of Blue Brook, between the ridges of First Watchung Mountain and Second Watchung Mountain. A dam near the headwaters of the creek creates Lake Surprise.
While there are playgrounds, golf courses, stables, and a museum within the reservation, much of the 1,945 acre (7.8 km2) parcel is forested, and the reservation is managed for the preservation of its natural resources.
The most popular recreational activities in the reservation are hiking and horseback riding on its many trails. The county-owned Watchung Stables are located on a large cleared area in the eastern end of the park, and at the center is the Trailside area, a large park with picnic tables and playground equipment.
The Trailside Nature & Science Center is at the southern edge, along Coles Avenue in Mountainside.
Climbers within the state have been drawn to the bouldering opportunities on the cliffs along the brook and Diamond Hill Road at the Watchung's western boundary, although climbing is technically prohibited by the county.
The land in the reservation has not been pristine and undeveloped for many years prior to and since the reservation's establishment. An entire village, Feltville, once existed in the woods in the northwestern quadrant. One popular hike in the western reservation goes through a pine plantation left by the Civilian Conservation Corps during the 1930s.
In spite of heavy local public protest, higher levels of government have taken land in the reservation twice for their own purposes. The first time was in the late 1950s when the U.S. Army built a Nike missile base and operated it between 1957 and 1963 to defend the airways over New York City. Today, the site has been redeveloped for use as Watchung Stables. A more lasting effect on the reservation came in the 1980s when, following years of litigation and public activism, the New Jersey Department of Transportation won approval for completion of Interstate 78 through the northern fringe of the reservation. Wildlife crossings designed to allow wildlife to travel safely between the severed parts of the Watchung Reservation were built.(Wikipedia)