Blue Mountain (Pennsylvania)

Blue Mountain[2]
Kittatinny Mountain (and nine others: Blue Hills Kau-ta-tin-chunk Kekaghtenemin Mountain Kightotinning Mountain Kittachtinny Hills Kittatinhy Mountain Kittochtinny Hills Kittochtinny Mountains North Mountain) [2][3]
The "Great Wall" of the Blue Mountain in Pennsylvania in February 2008
Highest point
Peak	Clarks Knob in Franklin County, Pennsylvania 2,320 feet (710 m)[4]
Elevation	1,129 ft (344 m)[2]
Coordinates	40°07′28″N 77°39′59″W / 40.12444°N 77.66639°W / 40.12444; -77.66639
Dimensions
Length	150 mi (240 km) northeast-southwest to SSW 150 miles (240 km) (direct aerial) 255 miles (410 km) trace of ridgeline, including loops back[5] width = varies along chain's length
Geography
Country	United States
State	Pennsylvania
Borders on	Ridge-and-Valley Appalachians Great Appalachian Valley
Geology
Orogeny	Appalachian Mountains
Rock age	Silurian
Rock types	Tuscarora Formation Shawangunk Formation; sedimentary

Blue Mountain, Blue Mountain Ridge, or the Blue Mountains of Pennsylvania is a ridge of the Appalachian Mountains in eastern Pennsylvania. Forming the southern and eastern edge of the Ridge-and-Valley Appalachians physiographic province in Pennsylvania, Blue Mountain extends 150 miles (240 km) from the Delaware Water Gap on the New Jersey border in the east to Big Gap in Franklin County in south-central Pennsylvania at its southwestern end.

Views of Blue Mountain dominate the southern tier of most eastern and central Pennsylvania counties, providing an ever-visible backdrop cutting across the northern or western horizon. Most transport corridors and road beds piercing the barrier necessarily pass through large water gaps, including (west to east) the Susquehanna, Schuylkill, Lehigh and Delaware River valleys or wind gaps, low gaps in the ridge caused by ancient watercourses. The barrier ridge forms a distinct boundary between a number of Pennsylvania's geographical and cultural regions.

To the south of the Susquehanna River gap in the south-central part of the state is the Cumberland Valley, part of the Great Appalachian Valley; to its northwest side are the southern reaches of the Susquehanna Valley with picturesque streams channeling travel corridors deep into and over the central and western mountains and valleys—the heartland interior counties of Pennsylvania; along the Main Branch Susquehanna, the valleys also lead into the Coal Region of northeast Pennsylvania, the Wyoming Valley, and the distant Poconos. To the south of Blue Mountain lies the Capital Region of Harrisburg and nearby communities, the rich farming country of the Lebanon Valley and Pennsylvania Dutch Country of York and Lancaster counties, the lower half of the Lehigh Valley, and the lower Delaware Valley, both of which extend north through water gaps beyond the ridgeline.

Blue Mountain School District, which is named after the mountain range, is located just off PA Route 61 in Schuylkill Haven, Pennsylvania.