Tussey Mountain is a stratigraphic ridge in central Pennsylvania, United States, trending east of the Bald Eagle, Brush, Dunning and Evitts Mountain ridges. Its southern foot just crosses the Mason-Dixon Line near Flintstone, Maryland, running north 130 km (80 mi) to the Seven Mountains of central Pennsylvania, near Tusseyville, making it one of the longest named ridges in this section of the Ridge-and-valley Appalachians. The ridge line separates Morrison Cove from the Woodcock Valley and Friends Cove from the Black Valley. Tussey Mountain lies in, and the ridge line forms parts of the borders of, Centre, Blair, Bedford and Huntingdon counties.
The Flintstone Creek runs around the southern end of the mountain in Maryland. North of there, small streams run through deep gorges, the Sweet Root and Rainsburg Gaps, near Martin Hill. At Everett the Pennsylvania Turnpike, U.S. Route 30, and the abandoned Huntingdon and Broad Top Mountain Railroad follow the Raystown Branch Juniata River through a deep water gap. The Yellow Creek runs through Loysburg Gap at Loysburg, Pennsylvania. Maple Run Road passes through a wind gap near Pulpit Hill, heading west to Woodbury. Pennsylvania Route 164 runs east out of Martinsburg, and climbs the west slope with a switchback before crossing the crest. The Frankstown Branch Juniata River runs north along the west foot of the ridge before turning east along U.S. Route 22 at Water Street, the river, road, and rail (abandoned PRR Petersburg Branch) crossing the ridge line through a water gap. The Little Juniata River passes through a nearby water gap at Spruce Creek along with the former Pennsylvania Railroad Main Line, which tunnels through a spur of the mountain to cut across a loop in the river. Galbraith Run passes through Galbraith Gap near the north end of the ridge, adjacent to the Tussey Mountain Ski Area in Boalsburg.
The Tussey Mountain Ridge is popular with soaring birds and glider pilots ridge soaring along its slopes. This ridge is part of a chain of ridges that stretch south to Tennessee. Tussey Mountain has been designated a Pennsylvania Important Bird Area (IBA), based primarily on its importance as a spring raptor migration site, but also as a long corridor of intact forest habitat, over 50% of which is publicly owned http://www.users.fast.net/~aquilac/tussey
. It is one of the best sites in the eastern United States for viewing the migration of the golden eagle. Pennsylvania's longest footpath, Mid State Trail, is atop or closely parallels Tussey Mountain for nearly its entire length.
In Blair County, Tussey Mountain is sometimes called Huntingdon Mountain, as one reaches Huntingdon by crossing it going east. Conversely, in some parts of Huntingdon County it is called Williamsburg Mountain as one reaches Williamsburg by crossing it going west.