Blue Mountain Ridge, Blue Mountain, or the Blue Mountains of Pennsylvania is part of the geophysical makeup of the Ridge-and-Valley Appalachians in the U.S. state of Pennsylvania. It is a ridge that forms the southern and eastern edge of the Appalachian mountain range spanning over from the Delaware Water Gap as it cuts across the eastern half of the state on a slight diagonal from New Jersey tending southerly until it turns southerly curving into Maryland, and beyond. Some distant view of The Blue Mountain dominates the southern tier of most eastern and central Pennsylvanian counties providing an ever visible backdrop cutting across the northern or western horizon. Most transport corridors and road beds piercing the barrier necessarily descend through either large water gaps or wind gaps their smaller tributary gaps cut by creeks, brooks, and lesser rivers. The descent into the southern lowlands are ramplike and before southbound travelers oft lays a scenic panorama spread from horizon to horizon. The barrier ridge forms a distinct boundary between a number of Pennsylvania's geographical and cultural regions. To the north of the Susquehanna Gap in the south-central part of the state are the Cumberland Valley tucked in the area above the water gap as if trying to flow through with the river; 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 northeast Pennsylvania, into the "Northern Coal Region", of the Wyoming Valley and the distant Poconos. To the Blue Mountain Ridge's center, on the southern side lies the "capital region", about 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; the latter two extend through water gaps beyond the ridgeline.
Geography
The ridge of Blue Mountain runs for through Pennsylvania, reaching an elevation of above sea level just north of the Pennsylvania Turnpike, near the borough of Newburg. Most of the ridgecrest, however, only reaches between and in elevation. The mountain's width varies from to. The southwestern end of the mountain is at Big Gap, west of Shippensburg. The northeastern end of the mountain is at the Delaware Water Gap on the New Jersey border. Mount Minsi forms the promontory overlooking the Delaware River. The ridge of Blue Mountain continues northeast into New Jersey as Kittatinny Mountain. Blue Mountain marks the boundary between the Great Appalachian Valley and the main Ridge-and-Valley Appalachians.
Water gaps
Four of Pennsylvania's major rivers cut through Blue Mountain in water gaps.
The Delaware River, which forms Pennsylvania's eastern border with New Jersey, passes through the ridge just southeast of Stroudsburg.
