Allegheny Portage Railroad National Historic Site is located between Johnstown and Hollidaysburg, Pennsylvania. It is situated in the Allegheny Mountains with elevations ranging from 346 m (1,135 ft) to 734 m (2,408 ft) above mean sea level.

The Allegheny Portage Railroad played a vital role in the nation's industrialization during the first half of the nineteenth century by linking the eastern United States to the west. Ten inclined planes allowed the railroad to overcome grades up to 5-6/8 degrees along the rugged terrain of the Allegheny Mountains, as the boats from the Pennsylvania Mainline Canal were portaged over the mountains.

Stretching across 36.6 miles, the park is narrow and linear. Natural resources common to the northeastern Appalachian region, such as oak forests and white-tailed deer, can be seen along the historic railroad trace and throughout the surrounding lands.