Interstate Highways in Washington, D.C.: Routes, Interchanges, Traffic, and Governance

Although Washington, D.C. is not a state, it is served by a complex network of Interstate Highways and U.S. Routes that connect the nation’s capital to Maryland, Virginia, and the broader Mid-Atlantic region. These highways support federal operations, daily commuting, tourism, and interstate commerce, carrying hundreds of millions of vehicle trips each year.

Who Owns and Maintains Interstate Highways in Washington, D.C.

Because the District of Columbia is not a state, responsibility for its highways is shared among multiple agencies:

• District Department of Transportation (DDOT): Maintains most roadway infrastructure within D.C.
• Federal Highway Administration (FHWA): Oversees Interstate Highway funding and standards.
• National Park Service (NPS): Manages highways and parkways on federal parkland (e.g., George Washington Memorial Parkway).
• Maryland Department of Transportation (MDOT): Maintains Interstate segments in Maryland.
• Virginia Department of Transportation (VDOT): Maintains Interstate segments in Virginia.

Primary Interstate Highways Serving Washington, D.C.

Interstate Four Hundred Ninety-Five (Capital Beltway)

Interstate Four Hundred Ninety-Five, commonly known as the Capital Beltway, forms a nearly complete loop around Washington, D.C., passing through Maryland and Virginia. The highway touches the District only briefly at the Woodrow Wilson Bridge, which crosses the Potomac River.

Major Interchanges and Connections

• Woodrow Wilson Bridge – connection to Interstate Ninety-Five
• Interchange with Interstate Two Hundred Ninety-Five (Anacostia Freeway)
• Connections to U.S. Route One, U.S. Route Fifty, and Maryland Route Two Hundred Ten

Traffic Volume

Average Annual Daily Traffic (AADT) on the Capital Beltway ranges from approximately 150,000 to over 250,000 vehicles per day depending on location, representing more than 60–90 million vehicle trips annually on key segments.

Interstate Sixty-Six

Interstate Sixty-Six begins near Georgetown in Washington, D.C. and extends westward through Northern Virginia, connecting with Interstate Four Hundred Ninety-Five and continuing toward Interstate Eighty-One in the Shenandoah Valley.

Major D.C. Interchanges and Exits

• U.S. Route Twenty-Nine (Whitehurst Freeway / K Street)
• Constitution Avenue and Independence Avenue
• Connection to Interstate Three Hundred Ninety-Five

Traffic Volume

Interstate Sixty-Six carries approximately 70,000 to 120,000 vehicles per day in the D.C. region, equivalent to roughly 25–45 million vehicle trips annually.

Auxiliary Interstate Highways in Washington, D.C.

Interstate Two Hundred Ninety-Five (Anacostia Freeway)

Interstate Two Hundred Ninety-Five runs northward from the Capital Beltway at the Woodrow Wilson Bridge, following the Anacostia River corridor into the eastern portion of Washington, D.C.

Major Exits and Connections

• South Capitol Street
• East Capitol Street
• Connection to Interstate Three Hundred Ninety-Five

Traffic Volume

Interstate Two Hundred Ninety-Five carries approximately 80,000 to 150,000 vehicles per day, or roughly 30–55 million vehicle trips annually.

Interstate Three Hundred Ninety-Five (Southwest Freeway)

Interstate Three Hundred Ninety-Five serves as a major north–south commuter corridor, linking downtown Washington, D.C. with Northern Virginia and Interstate Ninety-Five.

Major Exits and Connections

• New York Avenue (U.S. Route Fifty)
• Independence Avenue and Maine Avenue
• Connection to Interstate Six Hundred Ninety-Five

Traffic Volume

Interstate Three Hundred Ninety-Five carries approximately 90,000 to 180,000 vehicles per day, representing more than 35–65 million vehicle trips annually.

Interstate Six Hundred Ninety-Five (Southeast Freeway)

Interstate Six Hundred Ninety-Five is a short connector route linking Interstate Three Hundred Ninety-Five with Interstate Two Hundred Ninety-Five and local arterials near the U.S. Capitol.

Traffic Volume

This corridor carries approximately 50,000 to 90,000 vehicles per day, or roughly 18–33 million vehicle trips annually.

Cancelled and Unbuilt Interstate Projects

During the mid-twentieth century, planners proposed an extensive network of urban freeways in Washington, D.C., often referred to as the Inner Loop. Public opposition, environmental concerns, and urban preservation efforts led to the cancellation of most of these projects. Only limited segments were constructed, leaving Washington with a partial freeway system compared to other major U.S. cities.

Role of the Interstate System in Washington, D.C.

The Interstate Highway network in Washington, D.C. is essential for federal government operations, regional commuting, national security logistics, and tourism. Together, these highways carry an estimated hundreds of millions of vehicle trips each year, making them among the most heavily used urban Interstate corridors in the United States.

Interstate Highways in Washington, D.C.

• Interstate Four Hundred Ninety-Five (I-495)
• Interstate Sixty-Six (I-66)
• Interstate Two Hundred Ninety-Five (I-295)
• Interstate Three Hundred Ninety-Five (I-395)
• Interstate Six Hundred Ninety-Five (I-695)

U.S. Routes in Washington, D.C.

• U.S. Route One (US-1)
• U.S. Route Fifty (US-50)
• U.S. Route Twenty-Nine (US-29)