South Mountain (eastern Pennsylvania)

South Mountain is a colloquial name applied to features in the mountain range extending north and northeast from the Lebanon Valley to the Lehigh Valley regions of Pennsylvania. At times, it also been known as Texter Mountain, Durham Hills, Reading Hills, and the Lehigh Mountains. It is called the Reading Prong by geologists.[2] The name South Mountain is applied to the southernmost cluster of peaks in the feature, straddling Berks, Lancaster, and Lebanon counties;[3] and also to the northernmost end of the feature as the ridge into which Lehigh University is built.

South Mountain
South Mountain as viewed from Egypt, with Allentown in the foreground
Highest point
Peak	Womelsdorf Benchmark[1]
Elevation	1,380 ft (420 m)
Listing
Coordinates	40°19′28″N 76°11′44″W
Geography
Country	United States
State	Pennsylvania
Region	New England province
Counties	Berks, Lancaster, Lebanon Northampton and Lehigh
Parent range	Appalachian Highlands
Borders on	Lebanon Valley, Lehigh Valley and Piedmont
Biome	Ridge-and-Valley Appalachians
Geology
Orogeny	Grenville orogeny
Age of rock	Proterozoic eon and about 570 to 1,600 million years ago
Type of rock	Crystalline metamorphic rock and gneiss

South Mountain borders Emmaus, just to the south of Allentown, and comprises a ridge of low mountains passing east of Reading and then extending nearly due west. It is a continuation of the New England Province and is the southern end of the Hudson Highlands.[4]

The ridge does not follow a straight line like Blue Mountain, located to the north.

South Mountain ranges in elevation between 500 and 1,300 feet above sea level. The ridge is made of metamorphic rocks and gneiss, which date to the Precambrian era and range from about 570 to 1,600 million years old.

South Mountain is largely undeveloped in its northern extension due to conservation efforts and its steep slope. This makes it a beautiful backdrop to the viewpoints of the Lehigh Valley, including, at night, the city lights of Allentown. The southern end of this feature extends west along U.S. Route 422 and the southeastern border of Berks County, providing views of Blue Mountain (to the north), Mount Penn (which comprises part of the prong), and the city of Reading, to the east. The southernmost peaks were at one time home to many exclusive sanitariums and resorts, now all defunct except for the Caron Foundation. South Mountain serves as the transmitter site for local radio and television stations; independent TV station WFMZ-TV 69 has both its transmitter and studio facilities based on the mountain.