Haycock Mountain, locally called Ghost Mountain, is the highest summit in Bucks County and a prominent upland above Nockamixon State Park and Lake Nockamixon in southeastern Pennsylvania. Its name came from early settlers who thought its shape resembled a cock of hay. The mountain formed about 200 million years ago when magma intruded into shale and argillite in the Newark Basin, cooling into hard diabase as erosion later stripped away softer surrounding rock. That resistant geology left exposed ridge lines, large Triassic diabase boulders prized for bouldering, and nearby hornfels altered by heat. It also lies within the Tohickon Creek watershed and State Game Land 157.

Haycock, Pennsylvania · USA