The Dwight D. Eisenhower National System of Interstate and Defense Highways, commonly known as the Interstate Highway System, is a network of controlled-access highways that forms part of the National Highway System in the United States. The system extends throughout the contiguous United States and has routes in Hawaii, Alaska, and Puerto Rico.
Interstate 95 (I-95) is the main north–south Interstate Highway on the East Coast of the United States, running from U.S. Route 1 (US 1) in Miami, Florida, north to the Houlton–Woodstock Border Crossing between Maine and the Canadian province of New Brunswick. The highway largely parallels the Atlantic coast and US 1, except for the portion between Savannah, Georgia, and Washington, D.C., and the portion between Portland and Houlton in Maine, both of which follow a more direct inland route.
Interstate 97 (I-97) is a north-south Interstate Highway in the eastern United States. It runs entirely within Anne Arundel County, Maryland for 17.62 miles (28.36 km) from U.S. Route 50/U.S. Route 301 (US 50/US 301) in Parole near Annapolis north to I-695 and I-895 in Brooklyn Park near Baltimore. The Interstate is the primary highway between Baltimore and Annapolis. I‑97 connects Annapolis with Baltimore/Washington International Airport and links the northern Anne Arundel County communities of Crownsville, Millersville, Severna Park, Glen Burnie, and Ferndale. It is the second shortest primary Interstate Highway after I-87 in North Carolina.
Interstate 66 (I-66) is an east–west Interstate Highway in the eastern United States. The highway runs from an interchange with I-81 near Middletown, Virginia, on its western end to an interchange with U.S. Route 29 (US 29) in Washington, D.C., at the eastern terminus. Much of the route parallels US 29 or State Route 55 (SR 55) in Virginia. I-66 has no physical or historical connection to the famous US 66, which was located in a different region of the United States.
Interstate 380 (I-380) is a short 3.3-mile (5.3 km) east–west auxiliary Interstate Highway in the San Francisco Bay Area of Northern California, connecting I-280 in San Bruno to US Route 101 (US 101) near San Francisco International Airport. The highway primarily consists of only three intersections: I-280, State Route 82, and US 101. Like the nearby I-280, I-380 never connects to I-80, its parent Interstate Highway. However, there is no rule that says that spur routes need to.
Interstate 795 (I-795), also known as the Northwest Expressway, is a nine-mile (14 km) auxiliary Interstate Highway linking Baltimore's northwestern suburbs of Pikesville, Owings Mills, and Reisterstown, Maryland, to the Baltimore Beltway (I-695). The route bypasses Maryland Route 140, carrying part of the Maryland Transit Administration (MTA)'s Baltimore Metro SubwayLink in its median for a four-mile (6.4 km) stretch, and provides direct access to former Owings Mills Mall. It never connects to its parent, I-95, except via I-695.
The Woodrow Wilson Memorial Bridge, also known as the Woodrow Wilson Bridge or the Wilson Bridge, is a bascule bridge that spans the Potomac River between Alexandria, Virginia and Oxon Hill, Maryland in Prince George's County, Maryland. The original bridge was one of only a handful of drawbridges in the Interstate Highway System. It contained the only portion of the Interstate System owned and operated by the federal government until construction was completed and it was turned over to the Virginia and Maryland departments of transportation.
The Capital Beltway is a 64-mile (103 km) auxiliary Interstate Highway in the Washington metropolitan area that surrounds Washington, D.C., the capital of the United States, and its inner suburbs in adjacent Maryland and Virginia. It is the basis of the phrase "inside the Beltway", used when referring to issues dealing with US federal government and politics. The highway is signed as Interstate 495 (I-495) for its entire length, and its southern and eastern half runs concurrently with I-95.
Interstate 295 (I-295) in the US state of Maryland and in Washington, D.C., also known as the Anacostia Freeway, is a six-mile (9.7 km) auxiliary Interstate Highway connecting I-95/I-495 and Maryland Route 210 near the Potomac River to I-695 and District of Columbia Route 295 (DC 295) in the Anacostia neighborhood of Washington, D.C.
Interstate 395 (I-395) in Washington D.C. and Virginia is a 13.79-mile-long (22.19 km) spur route of I-95 that begins at an interchange with I-95 in Springfield and ends at an interchange with US Route 50 (US 50) in Northwest Washington, D.C. It passes underneath the National Mall near the US Capitol and ends at a junction with US 50 at New York Avenue, roughly one mile (1.6 km) north of the 3rd Street Tunnel. Despite its proximity to I-395 in Maryland, the route is unrelated and unconnected.
Interstate 270 (I-270) is a 34.7-mile (55.8 km) auxiliary Interstate Highway in the U.S. state of Maryland that travels from I-495 just north of Bethesda in Montgomery County north to I-70 in the city of Frederick in Frederick County. It consists of the 32.6-mile (52.5 km) mainline as well as a 2.1-mile (3.4 km) spur that provides access to and from southbound I-495. I-270 is known as the Washington National Pike, and makes up the easternmost stretch of the Dwight D. Eisenhower Highway. Most of the southern part of the route in Montgomery County passes through suburban areas around Rockville and Gaithersburg that are home to many biotech firms. This portion of I-270 is up to 12 lanes wide and consists of a local–express lane configuration as well as high-occupancy vehicle lanes that are in operation during peak travel times. North of the Gaithersburg area, the road continues through the northern part of Montgomery County, passing Germantown and Clarksburg as a six- to eight-lane highway with an HOV lane in the northbound direction only. North of here, I-270 continues through rural areas into Frederick County and toward the city of Frederick as a four-lane freeway.
Interstate 255 (I-255) is a bypass route of I-55 in Greater St. Louis. Along with I-270, it forms a loop around the central portion of the bi-state metro area; a majority of I-255 is located on the Illinois half. It shares its southern terminus with I-270 at the junction with I-55; I-270 and I-255 go to the west and east, respectively. U.S. Route 50 (US 50) joins I-255 at Lemay Ferry Road. It crosses the Mississippi River on the Jefferson Barracks Bridge, enters Illinois, and then turns northeast. There is a junction with I-64, where US 50 breaks off and goes east, and then further north there is a junction with I-55 again, I-70, and US 40, all of which are all cosigned together. The next junction is another one with I-270, which is the northern terminus of I-255. After that, the limited-access freeway continues on as Illinois Route 255 (IL 255). I-255 is 30.82 miles (49.60 km) in length.
Interstate 283 (I-283) is an auxiliary route of the Interstate Highway System located just east of Harrisburg, Pennsylvania. It travels from the Harrisburg East interchange of I-76 north to I-83/U.S. Route 322 at the Eisenhower Interchange. Pennsylvania Route 283 continues southeast from near the southern terminus of I-283 to Lancaster as a freeway, functioning as an extension of the Interstate, though they are two separate roads.
State Route 241 is a primary state highway in the U.S. state of Virginia. The state highway runs 1.88 miles (3.03 km) from U.S. Route 1 in Huntington north to SR 236 in Alexandria. SR 241 connects US 1 and SR 236, bypass Old Town Alexandria to the southwest. The state highway connects those highways with Interstate 95 and I-495, Huntington Avenue, and Eisenhower Avenue in a series of interchanges along the boundary of Fairfax County and the independent city of Alexandria. SR 241 also connects the above highways to the Huntington station of the Washington Metro, for which the portion of the highway from US 1 to the station is part of the National Highway System.
Interstate 95 (I-95) is an Interstate Highway running along the East Coast of the United States from Miami, Florida, north to the Canadian border in Houlton, Maine. In Maryland, the route is a major highway that runs 110.01 miles (177.04 km) diagonally from southwest to northeast, entering from the District of Columbia and Virginia at the Woodrow Wilson Bridge over the Potomac River, to Maryland's border with Delaware near Elkton. It is the longest Interstate Highway within Maryland and is one of the most traveled Interstate Highways in the state, especially between Baltimore and Washington, D.C., despite alternate routes along the corridor, such as the Baltimore–Washington Parkway, U.S. Route 1 (US 1), and US 29. Portions of the highway, including the Fort McHenry Tunnel and the Millard E. Tydings Memorial Bridge, are tolled.
Interstate 81 (I-81) is a part of the Interstate Highway System that runs from Dandridge, Tennessee, to Fishers Landing, New York. In Maryland, the Interstate Highway runs 12.08 miles (19.44 km) from the West Virginia state line at the Potomac River in Williamsport north to the Pennsylvania state line near Maugansville. I-81 is the primary north–south Interstate Highway in Washington County, connecting Hagerstown with Chambersburg and Harrisburg to the north and Martinsburg, Winchester, and Roanoke to the south.
