South Mountain Reservation, covering 2,110 acres, is a nature reserve on the Rahway River that is part of the Essex County Park System in northeastern New Jersey, United States. It is located in central Essex County, New Jersey, within portions of Maplewood, Millburn and West Orange, and borders South Orange, between the first and second ridges of the Watchung Mountains.Carved from wilderness at the end of the 19th century, designed by Olmsted Brothers, and developed over a few decades, the reservation has changed only slightly through the years. Preserved primarily in its wild state, woodlands abound in a variety of hardwood trees, and tall hemlocks tower above streams, creeks and ponds, and waterfalls. Higher points, such as Crater View, offer vistas of the New York and Jersey City skylines, Elizabeth, Union Township, and Staten Island.