Interstate 495 (Capital Beltway)

Interstate 495 (Capital Beltway)

I-495 shieldCapital Beltway marker

Interstate 495
Capital Beltway
Route information
Auxiliary route of I-95
Length: 64 mi[1][2] (103 km)
Existed: 1961 – present
Star-Spangled Banner Scenic Byway
Major junctions
Beltway around Washington, D.C.

I-295 near Forest Heights, MD
US 50 / I-595 near Glenarden, MD
MD 295 (BW Parkway) in Greenbelt, MD
I-95 near College Park, MD
I-270 near Bethesda, MD
SR 267 near Tysons Corner, VA
SR 7 in Tysons Corner, VA
I‑66 near Falls Church, VA

I‑95 / I‑395 near Springfield, VA
Highway system
MD 491 MD MD 495
I‑464 VA US 501
I‑395 DC I‑695

Interstate 495 (I-495) is a 64-mile (103 km) Interstate Highway that surrounds Washington, D.C., the capital of the United States of America, and the city's inner suburbs in adjacent Maryland and Virginia. I-495 is widely known as the Capital Beltway, the DC Beltway or simply the Beltway, especially when the context of Washington, D.C., is clear. It is the basis of the phrase "Inside the Beltway," used when referring to issues dealing with American government and politics. I-95 utilizes the southern and eastern half of the Capital Beltway to circumnavigate Washington, D.C., and is cosigned with I-495 along that route.

This Montgomery County in Maryland, and Fairfax County and the independent city of Alexandria in Virginia.

The Cabin John Parkway, a short connector between I-495 and the Clara Barton Parkway near the Potomac River along the Maryland–Virginia border, is considered an Interstate spur (I-495X) by the Maryland State Highway Administration.


  • Route description 1
    • I-95/I-495 concurrency in the District of Columbia 1.1
    • I-95/I-495 concurrency in Maryland 1.2
    • I-495 in Maryland 1.3
    • I-495 in Virginia 1.4
    • I-95/I-495 concurrency in Virginia 1.5
  • History 2
    • College Park Interchange 2.1
    • Traffic congestion 2.2
    • Current roadworks 2.3
    • HOT lanes 2.4
    • Exit numbering 2.5
  • Exit list 3
  • See also 4
  • Notes 5
  • References 6
  • External links 7

Route description

A Maryland stretch of Interstate 495 in October 2005.
Virginia-Welcomes-You sign on the Inner Loop over the Wilson Bridge. A short stretch of the bridge just before this sign is in the District of Columbia.

Except for the westernmost part of Woodrow Wilson Bridge south of downtown Washington (the water below is considered part of the District of Columbia), the Capital Beltway encircles Washington, D.C., in adjacent Maryland and Virginia. The two directions of travel, clockwise and counterclockwise (looking at a map), have become known respectively as the "Inner Loop" and the "Outer Loop". The route descriptions below follow the direction of the Outer Loop, starting at the Woodrow Wilson Bridge over the Potomac River, south of Washington.

Most Beltway interchanges provide access to Washington, with Clara Barton Parkway along the Maryland side of the river, and the Baltimore-Washington Parkway, approaching Washington from the northeast.

Originally, the entire Beltway was simply I-495, and I-95 was planned to serve downtown Washington, D.C., from the south and north, intersecting the Beltway in Virginia and in Maryland. However, environmental litigation stopped completion of this plan, and the built portion of I-95 inside the Beltway from the south northward into downtown Washington was redesignated I-395 in 1977. The small built portion from the north was converted into a park-and-ride lot. I-95 was then rerouted (and so signed) along the eastern side of the Beltway, with the I-495 designation left only along the western side. In 1989, the I-495 designation was returned to the eastern portion as well, with the highway co-signed as I-95 and I-495 along this route.

I-95/I-495 concurrency in the District of Columbia

The Beltway (here I-95 and I-495 together), four lanes in each direction, travels over the Federal Highway Administration recognizes 0.11 miles (0.18 km) of the bridge as crossing the tip of the southernmost corner of the District of Columbia.[3] However, signage for these boundary crossings is lacking.

I-95/I-495 concurrency in Maryland

The Beltway (here I-95 and I-495 together) enters Maryland during its Potomac River crossing over the Woodrow Wilson Bridge, west of Forest Heights and National Harbor. After crossing the Potomac, I-95/I-495 immediately meets the southern terminus of Interstate 295, known as the Anacostia Freeway, a route that serves downtown Washington to the north, connecting in Washington to Interstate 395. The highway next intersects MD 210, a major north–south route from southern D.C. to Indian Head in Charles County, Maryland.

I-95/I-495 and I-295 interchange in Maryland seen from the air above the Potomac River (2012)

Heading northeastward, the Beltway (I-95/I-495) interchanges with various local highways, including MD 5 and MD 4 on either side of Andrews Air Force Base, which the Beltway travels near its northern edge. (Both MD 5 and MD 4 extend westward into D.C., and southeastward into Southern Maryland.) Past the MD 4 interchange, the Beltway turns north through Glenarden, interchanging with MD 202.

The Beltway then interchanges with US 50/unsigned I-595, a major highway from downtown Washington eastward to Annapolis, Maryland, and the Chesapeake Bay Bridge to Maryland's Eastern Shore. Both US 50 and MD 450 (which interchanges with the Beltway slightly northward) provide access to the New Carrollton Metro, MARC commuter rail, and Amtrak stations, and the New Carrollton area.

Turning northwest, the Beltway then enters Greenbelt Park, intersecting the Baltimore-Washington Parkway (B-W Parkway) in the northeastern edge of the park. Just after the B-W Parkway, I-95/I-495 passes an interchange with MD 201, which connects to the southern terminus of the B-W Parkway at US 50 near the D.C. line. Now turned fully west, the Beltway runs through the northern edge of College Park, interchanging with the access roadway for the Greenbelt Metro and MARC commuter rail stations, then US 1.

Diagram of the College Park Interchange

Beyond the US 1 interchange, I-95 separates from I-495 at the College Park Interchange. I-495 continues west, alone, on the Capital Beltway, while I-95 turns northeast towards Baltimore, New York City, and Boston. The interchange includes access to a Park and Ride lot which was originally paved as part of I-95's route within the Beltway.

I-495 in Maryland

Continuing west from the College Park Interchange, I-495 crosses into Northwest Branch Park, the Beltway interchanges with MD 193 and US 29 south of Four Corners; the two interchanges are little more than 1/2 mile apart. Southbound US 29 is the main route into downtown Silver Spring, continuing into Washington.

Squeezing past Argyle Park and Sligo Creek Golf Course, the Beltway interchanges with MD 97 northwest of Silver Spring, then follows an alignment formerly known as Rock Creek Parkway.[1] The route twists along the alignment, through and around Rock Creek Park, then interchanges with MD 185 near the National Naval Medical Center. Turning northwest, I-495 soon encounters the southern terminus of Interstate 270, which extends westward to meet I-70 in Frederick, Maryland.

I-495/I-95 Northbound in Maryland, at the Rhode Island Ave. overpass

I-270 and I-495 split at a highly complex Y-junction, with separate HOV connections to I-270's HOV lanes and separate ramps to and from MD 355 (formerly US 240). The old Rock Creek Parkway alignment follows I-270 north, while I-495 turns west and enters the only other six-lane segment of the Beltway still in existence; significant levels of traffic exit onto I-270 north, leaving the six-lane segment west of the split adequate.

Interchanging with MD 187, I-495 soon meets the Interstate 270 Spur, the other side of the I-270/I-495 triangle. I-495 joins I-270 Spur at a converging wye junction; Inner Loop traffic exits from itself at the southern terminus of I-270 Spur, while Outer Loop traffic crosses the spur and enters it from the right. The two carriageways of I-495 temporarily widen to five lanes each until the MD 190 and Cabin John Parkway interchanges. (MD 190 provides access to the northwestern portion of Washington, D.C., and to the Potomac and Great Falls, Maryland areas of Maryland's Montgomery County, while the Cabin John Parkway extends to the Clara Barton Parkway along the Potomac River.)

After these interchanges, the Beltway then narrows to eight lanes again. Turning sharply to the west, I-495 meets the Virginia over the ten-lane American Legion Memorial Bridge.

I-495 in Virginia

I-495 in Virginia, seen from the Yellow Line of the Washington Metro

Immediately after crossing into trumpet interchange; the Parkway provides a scenic route to Arlington, Virginia, and downtown Washington. The Beltway then continues south, next interchanging with VA 193 south of Dranesville District Park, then reaches the extensive triangle of interchanges between I-495, the Dulles Airport Access Road, VA 267, and VA 123. The eastbound Dulles Access Road here also provides access to I-66 for Outer Loop Beltway traffic. The former interchange with the toll road (VA 267) is a directional interchange, while the latter is a cloverleaf; the entire complex occurs east of the Tysons Corner business district.

Now running south, the Beltway interchanges with VA 7 (Leesburg Pike) east of Tysons Corner; passing Dunn Loring to the east, I-495 soon reaches the complex interchange with Interstate 66, which extends westward to I-81 in the Shenandoah Valley near Strasburg, Virginia, and eastward to Arlington and downtown Washington. In a similar design as the I-270/I-495 interchange, dedicated HOV connections exist between I-495 and I-66, with many reversible and other directional ramps providing the remaining connections. There is no access between the Outer Loop and eastbound I-66 at this interchange. Instead, Outer Loop traffic must use the eastbound Dulles Access Road exit 3 miles (5 km) to the north in order to reach I-66 East.[2] There are multiple ramps from I-66 east to the Inner Loop, with one ramp exiting from the left side of I-66 east and the other exiting from the right.

South of the I-66 interchange, the Beltway crosses under US 29 and VA 237 with no access, then encounters a large braided interchange between I-495, US 50, and two local roads; the direct interchange between I-495 and US 50 is a full cloverleaf, while the braided local interchanges between I-495, US 50, and the local roads are modified SPUIs. The entire complex is bounded on the northeast side by Fairview Lake and on the southwest side by an office complex.

Continuing due south, the route then interchanges with Gallows Road, then skirts the eastern edge of Mill Creek Park before interchanging with VA 236 southwest of Annandale Community Park. Running along the eastern edge of Wakefield Park, the Beltway turns southeast and interchanges with VA 620 before turning east near Flag Run Park and entering Springfield, meeting the Springfield Interchange with I-95 southeast of the Shirley Industrial Complex.

I-95/I-495 concurrency in Virginia

"Maryland Welcomes You" sign on the Outer Loop over the Woodrow Wilson Bridge. Well before this shoreline point, in actuality, the highway leaves Virginia at the low-water mark,[4] briefly passes over an underwater corner of the District of Columbia, and enters Maryland for the rest of the Potomac River crossing.

I-95 joins the Beltway within the Springfield Interchange. I-495 also meets the southern terminus of Interstate 395 within the same massive interchange complex.

Running due east away from the interchange, crossing to the south of Backlick Stream Valley Park, the Beltway (now I-95/I495) interchanges with VA 613 a mile east of the Springfield Interchange. Continuing east, the Beltway encounters a diamond interchange with a connector road linking to Eisenhower Avenue, which parallels the Beltway for a short distance. Skirting the northern edges of Loftridge Park and Burgundy Park the two routes enter Alexandria and soon reach VA 241, a direct route into the city, currently under major reconstruction. Within the interchange, the Beltway nears the western approach to the Woodrow Wilson Memorial Bridge.

Continuing east the two routes encounter US 1, a major north-south highway providing access to Alexandria, Arlington and downtown Washington, as well as various points south in Fairfax County, Virginia. Finally, beyond this complex interchange, I-95 and I-495 together cross Alexandria's Jones Point Park and exit Virginia via the Woodrow Wilson Bridge.


The idea of building a highway around the Washington suburbs had been discussed at least since 1944, when Fred W. Tummler, director of planning of the National Capital Park and Planning Commission, proposed an Inter-County Metropolitan Freeway.[5] The Senate Public Works Committee backed the idea of building the highway in 1951, asking the Public Roads Bureau to prepare plans for the highway.[6] Backed by Senator Francis Case of South Dakota, the plan called for the highway to begin in Beltsville at the nearly completed Baltimore-Washington Parkway, continue west through Silver Spring and Bethesda, cross the Potomac River over a new bridge, head south near Tysons Corner and Falls Church, turn east by the Shirley Memorial Highway, and end at Route 1 in Gum Springs.[7] A 1952 amendment called for continuing the highway past Alexandria, over the Potomac River on a new bridge, and reconnect to the Baltimore-Washington Parkway in Maryland.[8] By December 1952, the plan had evolved into a highway that fully encircled Washington's suburbs.[9] The highway was intended to reduce traffic and also to offer an alternative route for the military in case of emergency.[6] The federal government gave final approval for the construction of the Capital Beltway (also known as the Circumferential Highway in the planning stages) on September 28, 1955. The first section of the 64-mile (103 km) long Beltway (including the Woodrow Wilson Memorial Bridge over the Potomac River) was opened on December 21, 1961; the highway was completed on August 17, 1964.

Originally designated I-495, in 1977 the eastern portion of the Beltway was re-designated

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