The Great Allegheny Passage runs from Cumberland, MD to Pittsburgh, PA. The area in Maryland where horses are permitted is between the Frostburg trailhead and the Mason & Dixon line. This area is located in Allegany County – Western Maryland. Trail Miles: 5 (one-way)  Day Use Parking is located at the Frostburg Trailhead. Parking area has limited space. Horse Camping: Read more...