Interstate 66



Interstate 66 links Washington, DC with Front Royal, Virginia and Interstate 81. The freeway serves commuter interests from Washington D.C. west to the growing Northern Virginia suburbs of Centerville, Manassas and Gainesville. Originally Interstate 66 was planned to connect to the planned alignment of Interstate 95 through Washington. It instead ends almost immediately after entering the District of Columbia at the Whitehurst Freeway (U.S. 29). It does not directly connect with Interstate 395, Interstate 695, or Interstate 295.

The routing of Interstate 66 in the District of Columbia is somewhat complicated, if only because of the lack of signage. After crossing the Potomac River via the Theodore Roosevelt Bridge, a sign indicates that Interstate 66 east continues north along the Potomac Freeway. The Potomac Freeway, a mostly unbuilt route planned to link the unconstructed Southwest Freeway (I-695) with Interstate 270, is a short freeway between the Roosevelt Bridge and U.S. 29 (Whitehurst Freeway). I-66 east along the Potomac Freeway is unsigned and green guide signs leading north only refer to the Whitehurst Freeway. However, from U.S. 29 (Whitehurst Freeway) north, Interstate 66 is signed as heading south on the Potomac Freeway.

Planned Improvements

The often congested stretch of Interstate 66 through Arlington County retains just four lanes overall. An addition of a third westbound lane was considered for the stretch of highway between Rosslyn and the Dulles Connector in 2003. Supported by Representatives Frank R. Wolf (R) and Thomas M. Davis III (R), the proposal was brought to Governor Mark R. Warner (D). The debate entailed concerns from Arlington officials involving potential problems that may accompany any traffic relief on that stretch. Thus options covering not only the addition of a westbound lane, but HOV lanes, toll lanes, transit opportunities, or leaving things as is were studied. County officials remained adamant in their opposition to any expansion of the existing roadway. Rep. Wolf however maintained that the highway may be expanded for only $18 million within the confines of the existing Interstate 66 "footprint", land already owned by the state. Many residents were not opposed to the potential project, and Wolf contested that the benefits of Interstate 66 expansion would also benefit adjacent streets and neighborhoods with potential relief.1

High Priority Corridor

Proposed Interstate 66 from Kansas to Kentucky is part of High Priority Corridor 3: TransAmerica Corridor. Its designation is written into law for the portion that travels through Kentucky.

Future Aspirations

Currently, plans call for an extension of Interstate 66 to the west. Added as a high priority corridor in 1991 and amended in recent transportation bills, Interstate 66 is the generally accepted designation for Corridor 3. In fact, the Fiscal Year 2002 Transportation Appropriations Bill added Interstate 66 as an Interstate Highway in the state of Kentucky, and signage was placed on the Cumberland Parkway in March 2005 to mark the future corridor. (To see this signage, visit Jeff Carlyle's Kentucky Roads page.) No construction has yet occurred on the new freeway, but the legislation facilitates adding new mileage to Interstate 66. A rough routing has been determined between Interstate 55 in Missouri east to Future Interstate 73/74 and U.S. 52 in West Virginia; the 2004 official map of Kentucky showed the anticipated corridor of the route. The existing Daniel Boone Parkway and Cumberland Parkway are generally planned to become part of the new Interstate highway.

The Interstate 66 East-West Trans-America Freeway was an idea hatched by Wichita business people in the early 1990s as a means to bring more business to southern Kansas. Interstate 66 would connect Fresno, California, with Washington, D.C., via the Four Corners, Wichita, and the width of Kentucky. They saw the business that Interstate 40 and Interstate 70 brought along their respective corridors, and they felt southern Kansas should have that kind of business too. Capitalizing on the fabled number "66," they determined that a new, coast-to-coast route would bring Kansas additional business. So the businessmen brought the idea to their politicians, and the politicians managed to get the idea listed as an ISTEA high priority corridor. Included with that congressional act was funding for a million dollar feasibility study.

Most of the proposed Interstate 66 is ambiguous and not even considered by state departments of transportation. However, the section of proposed Interstate 66 is defined by law between Interstate 57 in Missouri and Interstates 73/74 in West Virginia.

Interstate 66 has its designation written into law from Paducah to Pikeville in Kentucky, and future corridor signage was erected on eligible sections of the Cumberland (Louis Nunn) Parkway on March 23, 2005. This future designation was authorized in the December 2001 Transportation Appropriations Bill for Fiscal Year 2002, with $22.5 million allocated to Interstate 66. Interstate 66 is planned to be routed via the Cumberland Parkway and the Hal Rogers (formerly Daniel Boone) Parkway in southern Kentucky. The Cumberland Parkway is already Interstate compatible. All that will be required is eliminating the cloverleaf interchanges at the former toll booth locations at the U.S. 127 and U.S. 68 exits.

East of Interstate 75, the Interstate 66 corridor is proposed to follow Hal Rogers Parkway Parkway east to Exit 56 (Kentucky 451). Hal Rogers Parkway is a Super Two with passing lanes on the hills, with extensive reconstruction needed to become Interstate compatible. Currently, there is no freeway connector between the Cumberland and Hal Rogers Parkways, so one will have to be constructed.

East across the hills of eastern Kentucky, the I-66 corridor is projected to cross into West Virginia between Matewan and Edgarton. It is to end at the proposed King Coal Highway (Interstate 73/74) in West Virginia. The section of proposed Interstate 66 through Kentucky has a proponent web page at Interstate 66: TransAmerica Corridor (by the Kentucky Transportation Cabinet).

It is unclear how Interstate 66 in Kentucky would connect to Interstate 66 in Virginia. While this could be accomplished through U.S. 119 and U.S. 48/Corridor H via Charleston, it is not known if this is being considered. Corridor H in northeast West Virginia is partially built as a four-lane divided highway, but without full access control.

See The Trans America Corridor (Interstate 66) Page for more details.


Interstate 66 from Interstate 495 (Capital Beltway) east to Washington, D.C., was approved for federal funding on January 5, 1977, by Secretary of Transportation William T. Coleman, Jr. The freeway was built with four lanes and had truck restrictions. Additional restrictions were in place during commuting hours: cars with four or more occupants, buses, airport traffic, and emergency vehicles. The final section of Interstate 66 within the beltway opened to traffic on December 22, 1982. The Theodore Roosevelt Bridge, which carries Interstate 66 from Arlington, Virginia, east into the District of Columbia, opened to traffic on June 23, 1964.2

Parallel/Historic U.S. Routes

Interstate 66 largely parallels or replaces U.S. 211 between Interstate 81 and Washington, D.C.

Highway Guides

Western Terminus - Interstate 81 - Middletown, Virginia
Perspective from Interstate 66 west
With Little North Mountain rising in the distance, Interstate 66 west prepares to end at Exits 1A/B with Interstate 81. The northbound control city of Winchester is just 16 miles away while the West Virginia State line is crossed in 23 miles via I-81 north. Photo taken by Richard B. Rogers (12/27/02).
Milepost 0 of Interstate 66, posted about 30 meters before merging onto Interstate 81 south. Strasburg lies a short distance to the south. Photo taken by Richard B. Rogers (12/27/02).
Perspective from Interstate 81 south
The exit for Interstate 66 east from Interstate 81 south departs from the left. Front Royal is used as the westbound control city of Interstate 66 from Fairfax County westward. Interstate 81 meanwhile, straddles the Appalachians another 158 miles to reach the city of Roanoke. Photo taken by Brian LeBlanc (3/02).
More photos covering I-81 south at I-66 east posted at Interstate 81 South - Frederick & Warren Counties on AARoads.
Perspective from Interstate 81 north
Interstate 81 spans Cedar Creek and enters Frederick County on the one mile approach to Exit 300 with Interstate 66. A tri-level stack interchange joins the two freeways just east of parallel U.S. 11. Photo taken 07/24/04.
Exit 300 leaves I-81 north for Interstate 66 east to Washington. The first exit lies six miles ahead outside Front Royal. Photo taken 07/24/04.
Historical Perspective from Interstate 81 north
Older guide signs for I-81 north at I-66 simply referenced Winchester with no mention of North. These were replaced by the 2000s.
A 64 mile stretch of freeway separates Interstate 81 and the Capital Beltway / Interstate 495 while Front Royal is just nine miles to the southeast. Vidcap taken 05/27/95.
An older guide sign again for I-81 north at Exit 300 for I-66 east. The 6.6-mile stretch of Interstate 66 east from here to U.S. 340 & 522 opened in October 1971.3 Vidcap taken 05/27/95.
Eastern Terminus - U.S. 29 - Washington, D.C.
Perspective from Interstate 66 east
Interstate 66 & U.S. 50 split at the east end of the Theodore Roosevelt Bridge. U.S. 50 joins Constitution Avenue NW east along the National Mall while I-66 turns northward onto the Potomac Freeway. This is the last reference for the Interstate eastbound. Photo taken 08/04/13.
The Potomac Freeway passes through a cut and cover tunnel below Virginia Avenue NW and New Hampshire Avenue NW east of the Watergate Complex. Interstate 66 partitions beyond the tunnel into ramps for 27th Street SW, the Whitehurst Freeway (U.S. 29) and L Street NW to K Street NW (U.S. 29). Photo taken 08/04/13.
Additional coverage of the Interstate 66 eastern terminus posted at Interstate 66 D.C. guide on AARoads.
Perspective from U.S. 29 (Whitehurst Freeway) north
The Whitehurst Freeway travels east from the Francis Scott Key Bridge to an interchange with K Street and Interstate 66 (Potomac Freeway) west. U.S. 29 joins K Street east from the freeway end I-66 begins to the south. Photo taken 08/04/13.
More photos covering U.S. 29 north ahead of the split with Interstate 66 posted at the U.S. Route 29 D.C. page on AARoads.


  1. "Running Room on I-66." The Washington Post, September 8, 2003.
  2. Celebrating the 50th Anniversary of the Eisenhower Interstate Highway System: Previous Interstate Facts of the Day by the Federal Highway Administration (FHWA).
  3. Interstate 66 in Virginia (Roads to the Future web site).

Page Updated August 21, 2014.


State Virginia
Mileage 74.80
Cities Front Royal, Manassas, Fairfax, Vienna, Falls Church, Arlington
Junctions Interstate 81, Interstate 495
State District of Columbia
Mileage 1.48
Cities Washington
Junctions None
TOTAL 76.28
Source: December 31, 2014 Interstate Route Log and Finders List
Interstate 66 Annual Average Daily Traffic

State Location AADT Composite Year
Virginia Strasburg 24,000 2002
Virginia Fairfax 188,000 2002
Virginia Falls Church 131,000 2002
District of Columbia Washington 100,000 2000
Source: Virginia Department of Transportation 2002 AADT
2000 Traffic Volumes (District Division of Transportation - Traffic Services Division, Washington, D.C.)
Complete Interstate 66 AADT data.