Blue Mountain (Pennsylvania)

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 state's border with New Jersey in eastern Pennsylvania 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 Main Branch Susquehanna, the valleys lead to the Coal Region in Northeastern Pennsylvania Wyoming Valley, and the distant Pocono Mountains. To the south of Blue Mountain is the Capital Region and the state's capital of Harrisburg, the region's primary city, along with nearby communities in the rich farming regions of Lebanon Valley and Pennsylvania Dutch Country of York and Lancaster counties and the lower halves of both the Lehigh Valley and 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.