In general, the road climbed westwards along the Amerindian trail known as Chief Nemacolin's Path, once followed and improved by a young George Washington, then also followed by the Braddock Expedition.
Using the Cumberland Narrows, its first phase of construction crossed the Allegheny Mountains entered southwestern Pennsylvania, reaching the Allegheny Plateau in Somerset County, Pennsylvania.
There, travelers could turn off to Pittsburgh or continue west through Uniontown and reach navigable water, the Monongahela River, at Brownsville, Pennsylvania, which was by then a major outfitting center and riverboat-building emporium.
Many settlers boarded boats there to travel down the Ohio and up the Missouri, or elsewhere on the Mississippi watershed.

By 1818, travelers could press on, still following Chief Nemacolin's trail across the ford, or taking a ferry to West Brownsville, moving through Washington County, Pennsylvania, and passing into Wheeling, Virginia (now West Virginia), 45 miles (72 km) away on the Ohio River.
Subsequent efforts pushed the road across the states of Ohio and Indiana and into the Illinois Territory.
The western terminus of the National Road at its greatest extent was at the Kaskaskia River in Vandalia, Illinois, near the intersection of modern U.S. 51 and U.S. 40.

Today, travelers driving east from Vandalia travel along modern U.S. 40 through south-central Illinois.
The National Road continued into Indiana along modern U.S. 40, passing by the cities of Terre Haute and Indianapolis.
Within Indianapolis, the National Road used the original alignment of U.S. 40 along West and East Washington Street (modern U.S. 40 is now routed along I-465).
East of Indianapolis, the road went through the city of Richmond before entering Ohio, where the road continued along modern U.S. 40 and passed through the northern suburbs of Dayton, Springfield, and Columbus.
West of Zanesville, Ohio, despite U.S. 40's predominantly following the original route, many segments of the original road can still be found.
Between Old Washington and Morristown, the original roadbed has been overlaid by I-70.
The road then continued east across the Ohio River into Wheeling in West Virginia, the original western end of the National Road when it was first paved.
After running 15 miles (24 km) in West Virginia, the National Road then entered Pennsylvania.
The road cut across southwestern Pennsylvania, heading southeast for about 90 miles (140 km) before entering Maryland.
East of Keyser's Ridge, the road used modern Alternate U.S. 40 to the city of Cumberland (modern U.S. 40 is now routed along I-68).
Cumberland was the original eastern terminus of the road.
In the mid-19th century, a turnpike extension to Baltimore—along what is now Maryland Route 144 from Cumberland to Hancock, U.S. 40 from Hancock to Hagerstown, Alternate U.S. 40 from Hagerstown to Frederick, and Maryland Route 144 from Frederick to Baltimore—was approved.
The approval process was a hotly debated subject because of the removal of the original macadam construction that made this road famous.

The road's route between Baltimore and Cumberland continues to use the name National Pike or Baltimore National Pike and as Main Street in Ohio today, with various portions now signed as U.S. Route 40, Alternate U.S. 40, or Maryland 144.
A spur between Frederick, Maryland, and Georgetown (Washington, D.C.), now Maryland Route 355, bears various local names, but is sometimes referred to as the Washington National Pike; it is now paralleled by Interstate 270 between the Capital Beltway (I-495) and Frederick.
In general, the road climbed westwards along the Amerindian trail known as Chief Nemacolin's Path, once followed and improved by a young George Washington, then also followed by the Braddock Expedition. Using the Cumberland Narrows, its first phase of construction crossed the Allegheny Mountains entered southwestern Pennsylvania, reaching the Allegheny Plateau in Somerset County, Pennsylvania. There, travelers could turn off to Pittsburgh or continue west through Uniontown and reach navigable water, the Monongahela River, at Brownsville, Pennsylvania, which was by then a major outfitting center and riverboat-building emporium. Many settlers boarded boats there to travel down the Ohio and up the Missouri, or elsewhere on the Mississippi watershed.
By 1818, travelers could press on, still following Chief Nemacolin's trail across the ford, or taking a ferry to West Brownsville, moving through Washington County, Pennsylvania, and passing into Wheeling, Virginia (now West Virginia), 45 miles (72 km) away on the Ohio River. Subsequent efforts pushed the road across the states of Ohio and Indiana and into the Illinois Territory. The western terminus of the National Road at its greatest extent was at the Kaskaskia River in Vandalia, Illinois, near the intersection of modern U.S. 51 and U.S. 40.
Today, travelers driving east from Vandalia travel along modern U.S. 40 through south-central Illinois. The National Road continued into Indiana along modern U.S. 40, passing by the cities of Terre Haute and Indianapolis. Within Indianapolis, the National Road used the original alignment of U.S. 40 along West and East Washington Street (modern U.S. 40 is now routed along I-465). East of Indianapolis, the road went through the city of Richmond before entering Ohio, where the road continued along modern U.S. 40 and passed through the northern suburbs of Dayton, Springfield, and Columbus. West of Zanesville, Ohio, despite U.S. 40's predominantly following the original route, many segments of the original road can still be found. Between Old Washington and Morristown, the original roadbed has been overlaid by I-70. The road then continued east across the Ohio River into Wheeling in West Virginia, the original western end of the National Road when it was first paved. After running 15 miles (24 km) in West Virginia, the National Road then entered Pennsylvania. The road cut across southwestern Pennsylvania, heading southeast for about 90 miles (140 km) before entering Maryland. East of Keyser's Ridge, the road used modern Alternate U.S. 40 to the city of Cumberland (modern U.S. 40 is now routed along I-68). Cumberland was the original eastern terminus of the road. In the mid-19th century, a turnpike extension to Baltimore—along what is now Maryland Route 144 from Cumberland to Hancock, U.S. 40 from Hancock to Hagerstown, Alternate U.S. 40 from Hagerstown to Frederick, and Maryland Route 144 from Frederick to Baltimore—was approved. The approval process was a hotly debated subject because of the removal of the original macadam construction that made this road famous.
The road's route between Baltimore and Cumberland continues to use the name National Pike or Baltimore National Pike and as Main Street in Ohio today, with various portions now signed as U.S. Route 40, Alternate U.S. 40, or Maryland 144. A spur between Frederick, Maryland, and Georgetown (Washington, D.C.), now Maryland Route 355, bears various local names, but is sometimes referred to as the Washington National Pike; it is now paralleled by Interstate 270 between the Capital Beltway (I-495) and Frederick.
National Road