The National Road—formerly the Cumberland Road and later celebrated as "Main Street of America"—was the United States' first great federally financed highway and a proving ground for national‑scale internal improvements. Originating at the head of navigation on the Potomac River in Cumberland, Maryland, the 4-rod (66 ft; 20 m) wide engineered turnpike was authorized on March 29, 1806 when President Thomas Jefferson signed "An Act to regulate the laying out and making a road from Cumberland … to the State of Ohio". Surveyors ran a 131-mile (211 km) alignment over the Allegheny Mountains to Wheeling, Virginia, on the Ohio River by 1818, building a stone‑surfaced, cambered roadway, masonry bridges, culverts, and cast‑iron mileposts that set standards for antebellum turnpikes. Between 1825 and 1838, Congress approved successive appropriations that pushed the highway westward across Ohio, Indiana, and into Illinois. Construction gangs reached Zanesville in 1833, Columbus in 1834, the eastern outskirts of Indianapolis in 1836, Terre Haute in 1838, and the then‑capital of Vandalia, Illinois—591 mi (951 km) from Cumberland—by 1839, when federal contracts ceased. From 1806 to 1838, Congress appropriated about $6.8 million for surveys, right‑of‑way acquisition, grading, stone surfacing, and masonry—an unprecedented federal outlay for transportation infrastructure. The project triggered widespread debates over the constitutional scope of "internal improvements". The operation and maintenance of completed segments were transferred to the states in stages—Maryland (1833), Pennsylvania (1836), Virginia (now West Virginia) (1838), Ohio (1849), Indiana (1849), and Illinois (1856). Traffic declined with the rise of canals and railroads, but many portions were rebuilt in concrete or brick during the 1910s–1930s and incorporated into U.S. Route 40. In the 20th century, with the advent of the automobile, the National Road was connected with other historic routes to California under the title, National Old Trails Road. Today, much of the alignment is followed by U.S. Route 40 (US 40), with various portions bearing the Alternate U.S. Route 40 (Alt. US 40) designation, or various state-road numbers (such as Maryland Route 144 for several sections between Baltimore and Cumberland). Scholars regard the National Road as a foundational step toward the modern Interstate Highway System. In 1976, the American Society of Civil Engineers designated the National Road as a National Historic Civil Engineering Landmark. In 2002, the entire road, including extensions east to Baltimore and west to St. Louis, was designated the Historic National Road, an All-American Road. The surviving corridor, which includes historic tollhouses, stone‑arch and iron bridges, and intact macadam sections, is now listed on the National Register of Historic Places.