Cushetunk Mountain

Cushetunk Mountain is a horsehoe-shaped mountain located in Readington and Clinton Township, New Jersey.

It was formerly known as Mount Ployden, Pickel's Mountain and occasionally as Mount Cushetunk or Coshanton. The Lenape called the mountain "Cushetunk" meaning "place of hogs" after the wild hogs that were found there.

Before the arrival of Europeans, Cushetunk Mountain was inhabited by Unami speaking Lenape, particularly the Musconetcongs who ranged between Cushetunk Mountain and Sourland Mountain to the south. An interesting claim put forward by Beauchamp Plantagenet, one of the first Europeans to explore the area around the mountain, states that a Native American king held his seat in a place resembling the valley formed by Cushetunk Mountain. The claim exists today as a legend, and no evidence has ever been found confirming Plantagenet’s story of a ‘Raritan king’.

In the 1960s, the valley at the heart of the mountain was dammed and filled with water to create Round Valley Reservoir.

The mountain’s U-shaped arc is approximately two miles in diameter, with the more massive portion of the mountain occupying the southwest corner of the ridgeline. The man-made lake, Round Valley Reservoir, occupies the valley at the center of the horseshoe.


Cushetunk Mountain is occasionally referred to as a mountain range and includes Round Mountain, a 610 foot peak located about a mile and a half south of Cushetunk Mountain in Readington. Round Mountain is linked to Cushetunk Mountain by a sheet of intruded diabase rock running beneath the surface.

Two famous names from New Jersey’s colonial history owned land on the north slope of Cushetunk Mountain in Potterstown (part of Readington and Clinton Township). One was John Stevens, a delegate to the Continental Congress, whose grandson founded Stevens Institute of Technology. The other was Lord Stirling, an American Revolutionary War General who was ranked 3rd or 4th behind George Washington.


Contrary to popular belief, the ring-like shape of the mountain does not represent a crater, particularly since the mountain was formed primarily within the Earth. Instead, the mountain’s shape seems to be the result of an intruding sheet of magma becoming dramatically flexed as it penetrated local strata.

While most of the mountain ridges in New Jersey run generally north to south, Cushetunk Mountain primarily has an east-west ridge orientation because of the elongated north and south prongs of its horseshoe-like ridge. This produces significantly different microclimates between the north facing and south facing slopes of the mountain.

Because the north slope of the mountain is cooler and shaded, moisture is more easily retained. This results in larger trees, as well as the growth of trees not seen on southern facing slopes. These trees include black birch, tulip tree, white ash, basswood, hickory, beech, and sugar maple. Shrubs are abundant in the understory of the northern slopes, as well as herbs typical of more northern forests, including wild ginger, wild sarsaparilla, black snakeroot, and columbine.

On the warmer, dryer southern slopes chestnut oak and red oak prevail, although the trees are also common to the northern slopes. In the understory, dogwood is dominant, and the diversity and number of shrubs is reduced. Grasses and sedges are the most prevalent ground cover.

Wildlife supported by Cushetunk Mountain includes a variety of woodland birds, including a nesting pair of bald eagles. Groundwater seeps, particularly on the northern slopes, provide habitat to amphibians, while outcrops of trap rock offer ideal environments for small reptiles.