Capital Beltway
The Capital Beltway, designated as Interstate 495 for its entire length, is an auxiliary Interstate Highway in the Washington metropolitan area. The beltway encircles Washington, D.C., the capital of the United States, and its inner suburbs in adjacent Maryland and Virginia. It also passes through the capital, near the western end of the Woodrow Wilson Bridge over the Potomac River; Prince George's and Montgomery counties in Maryland and Fairfax County; and the independent city of Alexandria in Virginia.
The route is the basis of the phrase "inside the Beltway", used when referring to issues dealing with U.S. federal government and politics. Its southern and eastern half runs concurrently with I-95. It was constructed in 1964. 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 by the Maryland State Highway Administration.
Route description
Except for the westernmost part of Woodrow Wilson Bridge south of Downtown, the Capital Beltway encircles Washington, D.C., in adjacent Maryland and Virginia. The two directions of travel, clockwise and counterclockwise, 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 I-95 and I-295 from the south, I-66 from the west, and U.S. Route 50 from the west and the east are among the most frequently used. More scenic routes from the beltway into DC are offered by the George Washington Memorial Parkway along the Virginia side of the Potomac River, the Clara Barton Parkway along the Maryland side of the river, and the Baltimore–Washington Parkway, approaching Washington DC from the northeast.
Initially, the entire beltway was simply I-495, and I-95 was planned to serve Downtown from the south and north, intersecting the beltway in Virginia and Maryland. The Virginia segment from Springfield to the D.C. border was completed—however, environmental litigation stopped the completion of the Maryland segment, and the built portion of I-95 inside the beltway from the south northward into Downtown 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 along the eastern side of the beltway, with the I-495 designation left only along the western side, leaving both routes as bypasses of Washington, D.C. In 1989, the I-495 designation was also returned to the eastern portion, with the highway cosigned as I-95 and I-495 along this route.
District of Columbia
The beltway—here I-95 and I-495 together and four lanes in each direction—travels over the tidal Potomac River on the Woodrow Wilson Bridge between Alexandria, Virginia, and the neighborhood of National Harbor of Oxon Hill, Maryland. The Federal Highway Administration recognizes of the bridge as crossing the tip of the southernmost corner of the District of Columbia, but, while there are signs acknowledging the Maryland and Virginia state borders, there are none for DC.Maryland
Prince George's County
The beltway enters Maryland during its Potomac River crossing over the Woodrow Wilson Bridge, west of Forest Heights and National Harbor as a 10-lane highway with a local–express lane configuration including three local lanes and two express lanes in each direction. After crossing the Potomac River, I-95/I-495 narrows to eight lanes with two local and two express lanes in each direction and immediately meets the southern terminus of I-295, known as the Anacostia Freeway, a route that serves Downtown to the north, connecting in Washington, D.C., to I-695. This large interchange also connects to National Harbor Boulevard, which links the National Harbor with the beltway and I-295. The highway passes south of Oxon Cove Park and Oxon Hill Farm and next intersects Maryland Route 210, a major north–south route from southern DC to Indian Head in Charles County, which also serves the town of Forest Heights to the north at another interconnected interchange.Heading eastward, the beltway's local–express lane configuration ends before it 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. 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 eastward to Annapolis and the Chesapeake Bay Bridge to the Eastern Shore of Maryland. Both US 50 and MD 450 provide access to New Carrollton serving Washington Metro's Orange Line, MARC Train's Penn Line, and Amtrak's Northeast Corridor railroad line and the New Carrollton area.
Turning northwest, the beltway then enters Greenbelt Park, intersecting the B–W Parkway on 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 DC line. Now turned fully west, the beltway runs through the northern edge of College Park, interchanging with the access roadway for Greenbelt station serving Washington Metro's Green Line and MARC Train's Camden Line in Greenbelt, then US 1.
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 toward Baltimore. The interchange includes access to a park-and-ride lot, paved initially as part of I-95's route within the beltway.
Montgomery County
Continuing west from the College Park Interchange, I-495 crosses into Montgomery County, entering a heavily developed and populated area. Passing underneath MD 212 with no access, the route interchanges with MD 650 near the George Washington Cemetery. After bisecting Northwest Branch Park, the beltway interchanges with MD 193 and US 29 south of Four Corners; the two interchanges are little more than half a mile apart. Southbound US 29 is the main route into downtown Silver Spring, continuing into Washington, D.C.Squeezing past Argyle Local 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. The route twists along the alignment, through and around Rock Creek Park, then interchanges with MD 185 near the Walter Reed National Military Medical Center. Turning northwest, I-495 soon encounters the southern terminus of I-270, which extends northwestward to meet I-70 in Frederick.
I-270 and I-495 split at a highly complex Y junction, with two separate high-occupancy vehicle connections to I-270's HOV lanes and separate ramps to and from MD 355. 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 Old Georgetown Road, I-495 soon meets the I-270 Spur, the other side of the I-270/I-495 triangle. I-495 joins I-270 Spur at a converging Y 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.
After these interchanges, the beltway then narrows to eight lanes again. Turning sharply to the west, I-495 meets the Clara Barton Parkway along the north side of the Potomac River; this parkway provides a scenic route eastward into the western part of Washington, D.C., and westward toward the Potomac River's Great Falls. After this interchange, the Beltway soon crosses the Mather Gorge into Virginia over the 10-lane American Legion Memorial Bridge.
Virginia
Immediately after crossing into Fairfax County, I-495 encounters the western terminus of the George Washington Memorial Parkway at a trumpet interchange; the parkway provides a scenic route to Arlington and Downtown. The beltway then continues south, next interchanging with State Route 193 south of Dranesville District Park, then reaches the extensive triangle of interchanges between I-495, the Dulles Access Road, SR 267, and SR 123. The eastbound Dulles Access Road also provides access to I-66 for Outer Loop beltway traffic. The former interchange with the toll road is a directional interchange, while the latter is a cloverleaf; the entire complex occurs east of the Tysons business district.Now running south, the beltway interchanges with SR 7 east of Tysons; passing Dunn Loring to the east, I-495 soon reaches the complex interchange with I-66, which extends westward to I-81 in the Shenandoah Valley near Strasburg and eastward to Arlington and Downtown. In a similar design as the I-270/I-495 interchange, dedicated HOV connections exist between I-495 and I-66, with 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 to the north in order to reach I-66 east. 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. The Dulles Access Road leads to Dulles International Airport, which then changes over to the Dulles Greenway and ends at Leesburg.
South of the I-66 interchange, the beltway crosses under US 29 and SR 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 single-point urban interchanges. 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 SR 236 southwest of Annandale Community Park. Running along the eastern edge of Wakefield Park, the Beltway turns southeast and interchanges with SR 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 joins the beltway within the Springfield Interchange. I-495 also meets the southern terminus of I-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 interchanges with SR 613 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 and Burgundy parks, the two routes enter Alexandria and soon reach SR 241, a direct route into the city. Within the interchange, the beltway nears the western approach to the Woodrow Wilson Bridge.
Continuing east, the two routes encounter US 1, a major north–south highway providing access to Alexandria, Arlington, and Downtown, as well as various points south in Fairfax County. 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.