U.S. Route 40 (Baltimore–Philadelphia)

U.S. Route 40 (Baltimore–Philadelphia)
State	MD
Route	40
Type	US
Length mi	approximately 45
Direction a	West
Terminus a	I-95 in Baltimore
Direction b	East
Terminus b	I-95 in Philadelphia

U.S. Route 40 (Baltimore–Philadelphia) is a historic segment of the United States Numbered Highway System linking Baltimore and Philadelphia via a corridor that follows earlier colonial roads, turnpikes, and 19th‑century routes. The alignment traverses urban neighborhoods, industrial districts, suburbs, and historic towns, connecting major nodes such as Baltimore–Washington Parkway, Baltimore Harbor, Wilmington, Delaware, and University City, Philadelphia. The corridor parallels and intersects multiple interstates and rail lines, reflecting layered transportation planning involving agencies like the Maryland State Highway Administration and Pennsylvania Department of Transportation.

Route description

The route begins within Baltimore near the convergence of I-95 and the Fort McHenry Tunnel approaches, passing landmarks including Fort McHenry National Monument and Historic Shrine, Inner Harbor, Oriole Park at Camden Yards, and Baltimore Penn Station. Proceeding northeast, it follows historic alignments through neighborhoods adjacent to Jones Falls Expressway and crosses suburban counties such as Baltimore County and Harford County before reaching the Susquehanna River approaches toward Chesapeake Bay corridor roads. Into Delaware, the highway traverses the Brandywine Valley and urbanized corridors through Wilmington near Christiana Mall and Delaware River approaches, interacting with crossings used by Amtrak and SEPTA Regional Rail lines.

Entering Pennsylvania, the route penetrates the western suburbs of Philadelphia County, running through affluent and industrial districts near Haverford, Conshohocken, and across the Schuylkill River corridor approaching Center City Philadelphia. Its urban terminus connects to the Benjamin Franklin Parkway and interchanges with I-76 (Pennsylvania), I-676 (Pennsylvania), and the Vine Street Expressway, situating it among institutions such as University of Pennsylvania, Temple University Hospital, Philadelphia Museum of Art, and Independence National Historical Park.

History

The corridor follows parts of colonial roads like the King's Highway and the Lincoln Highway precursor alignments, later formalized by 19th‑century turnpikes such as the Baltimore and Philadelphia Turnpike and the Lancaster Pike. During the early 20th century, improvements were driven by organizations including the American Association of State Highway Officials and private entities like the Lincoln Highway Association. Federal designation as part of the U.S. Highway System in 1926 assigned the US‑40 number to this corridor, linking it to coast‑to‑coast ambitions evident in contemporaneous projects such as the National Road and Victory Highway.

Mid‑century highway construction, including the development of Interstate 95 (Delaware–Maryland), the expansion of I-76 (Pennsylvania), and urban renewal initiatives in Baltimore and Philadelphia, led to realignments, bypasses, and truncations. Preservation efforts around sites like Fort McHenry, Brandywine Battlefield, and Independence Hall influenced routing and interchange design. Recent decades have seen rehabilitation projects coordinated by Historic Preservation Society of Pennsylvania and state historic commissions, balancing traffic capacity with protection of sites like Elfreth's Alley and Christ Church.

Major intersections

- Terminus interchange with I-95 near Baltimore and access to Fort McHenry National Monument and Historic Shrine. - Junction with I-695 (Baltimore Beltway) providing access to BWI Airport and Patterson Park corridors. - Crossing and connector to US‑1 and US‑29 feeder routes in suburban corridors. - Interchange with Delaware Route 1 and proximity to Christiana Mall and Wilmington Station in Delaware. - Intersection with I-495 (Delaware bypass) and crossings near Brandywine Creek. - Connections to I-76 and the Schuylkill Expressway near Conshohocken and University City. - Junctions with I-676 and the Vine Street Expressway feeding into central Philadelphia and landmarks including Benjamin Franklin Bridge access. - Eastern terminus confluence with I-95 near Center City Philadelphia and access to Independence National Historical Park.

Related highways and connectors

This corridor intersects and parallels numerous federal and state routes: I‑95, I‑76, I‑695, U.S. Route 1, U.S. Route 13, U.S. Route 30, Delaware Route 273, Maryland Route 7, and Pennsylvania Route 3. Regional connectors include the Baltimore–Washington Parkway and the Benjamin Franklin Parkway, while freight and passenger rail corridors such as Amtrak's Northeast Corridor and CSX Transportation lines run adjacent. Local transit interfaces with Maryland Transit Administration bus routes, SEPTA operations, and MARC Train commuter services at multimodal nodes like Baltimore Penn Station and Wilmington Station.

Future developments and improvements

Planned improvements are coordinated by Maryland Department of Transportation, Delaware Department of Transportation, and Pennsylvania Department of Transportation with input from regional planning agencies such as the Delaware Valley Regional Planning Commission and the Baltimore Metropolitan Council. Projects include intersection upgrades, multimodal access enhancements connecting BWI Airport to urban transit, bridge rehabilitations over the Susquehanna River approaches, and corridor resilience work addressing stormwater and climate impacts. Funding proposals reference federal programs like the Infrastructure Investment and Jobs Act and grant opportunities administered by the Federal Highway Administration. Preservation-minded improvements aim to protect adjacent historic resources including Fort McHenry, Brandywine Battlefield, and Independence Hall while improving freight mobility for entities such as Port of Baltimore and intermodal facilities servicing Philadelphia International Airport and regional distribution centers.

Category:U.S. Highways in Maryland Category:U.S. Highways in Pennsylvania