The Allegheny Front near Altoona, PA. 

The Allegheny Mountains are a ubiquitous character in many of the stories of western Pennsylvania.  The following description is an excerpt from Indian Villages and Place Names in Pennsylvania by George P. Donehoo, originally published in 1925.  (Note:  the original spelling has been preserved.)

"Allegheny Mountains.  This name is often applied to the entire Appalachian mountain system, which runs along the eastern part of the continent [of North America].  The name, however, as used by all of the early explorers and traders, applied to the chief range of the Appalachian system.  This range, which is the most lofty and the hardest to cross, is the third range from the Ohio Valley, the first range being the Chestnut and the second the Laurel.  All of the early maps and explorers' journals so note these three ridges.  The Allegheny Mountain crosses the State about ten miles west of Bedford, Schellberg being near the foot of the eastern slope, and is the range through which the P. R. R. [Pennsylvania Railroad] passes at Kittanning Point, at the Horseshoe Bend.  The Allegheny Mountain presented the greatest difficulties in the way of all of the early traders, road makers and railroad builders in reaching the Ohio from the East.  Washington, Gist, Braddock, Post, Forbes and all others found this great mountain barrier the one supreme difficulty in the path to the Ohio region.  The French, who had reached the Ohio by way of the Allegheny [River], from the North, thought that it was impossible for the English to send an army over the lofty summits of the impassable Alleghenies.  There are but three natural gaps through this grand mountain range within the State of Pennsylvania -- that cut by the Youghiogheny, by the Conemaugh, and, far to the northward, by the West Branch adn the Allegheny.  The Indians took this northern course long before the coming of the white race to the continent.  According to the Jesuit Relation, the Black Minquaas and the Wenro traded on the upper waters of the Delaware long before the coming of the traders to the Ohio.  The course followed by these prehistoric travelers was from the upper Allegheny to the West Branch, to Shamokin (now Sunbury), up to Wyoming (now Wilkes-Barre) and across the Water Gap on the Delaware, near Easton.  This was, beyond doubt, the earliest path through the Allegheny Mountains.  Zeisberger followed it in part in 1767, when he went to the mouth of the Tionesta.  The next path, southward, was across from Kittanning to the West Branch, at Clearfield, or to the Juniata, over Kittanning Point, and down to the Susquehanna.  South of this path was the main road to Allegheny of the traders and Indians after the migration of the Delaware and Shawnee to the Ohio, early in the 18th Century.  The course of this path was from Harrisburg, by various gaps in the Blue Mountains, to Bedford and then by way of Ligonier and the Kiskiminetas Valley to Kittanning, or Shannopin's Town (now Pittsburgh).  The southern trail ran from Cumberland, Md., over the mountains to Mount Braddock, Connellsville, Mount Pleasant and on to Pittsburgh.  This was the course followed by General Braddock in 1755, General Forbes taking the middle path, by way of Bedford and Ligonier.