While the National Road (US 40) largely follows Braddock's Road across the Appalachian Mountains from Cumberland into Pittsburgh, Forbes' Road through south central Pennsylvania occasionally dissolves into a morass of speculation from Rohr's Gap (on the Allegheny Front west of Schellsburg) to Murrysville, Pennsylvania, with only a few certain locators. In the most general sense, the Pennsylvania Turnpike follows the trend of Forbes's Road west from Carlisle, Pennsylvania to near Monroeville, Pennsylvania just east of Pittsburgh, at places obliterating the historic road. A slightly more accurate rendition of Forbes's Road may be achieved by following US 30 from Chambersburg to the junction of SR 66 west of Greensburg, then north on the latter to US 22 east of Murrysville. US 22 west eventually connects with Penn Avenue, which may be followed to the sites of Fort Duquesne and Fort Pitt. A number of historical markers may be found along this route.