Interstate 66 - Definition and Overview

Interstate 66 is an interstate highway in the eastern United States. Its western terminus is at Middletown, Virginia at an intersection with Interstate 81; its eastern terminus is at Washington, D.C. at an intersection with United States Highway 29.

Length

Major Cities Along the Route

• Washington, D.C.

Intersections with other Interstates

• Interstate 81 in Middletown, Virginia
• Interstate 495, the Capital Beltway at Falls Church, Virginia

Interchanges

• Exit 1A I-81 south - Roanoke westbound only
• Exit 1B I-81 north - Winchester westbound only
• Exit 6 US 340/US 522 - Winchester/Front Royal
• Exit 13 Route 79 to Route 55 - Linden/Front Royal
• Exit 18 Route 688 - Markham
• Exit 23 Route 731 to US 17 north/Route 55 west - Delaplane/Paris eastbound only
• Exit 23 US 17 north/Route 55 west - Delaplane/Paris westbound only begin US 17/Route 55 concurrency
• Exit 27 Route 55 east/Route 647 (BUS US 17) - Marshall end Route 55 concurrency
• Exit 28 US 17 south/BUS US 17 - Marshall/Warrenton/Fredericksburg end US 17 concurrency
• Exit 31 Route 245 - The Plains/Old Tavern
• Exit 40 US 15 - Haymarket/Leesburg
• Exit 43 US 29 - Gainesville/Warrenton
• Exit 44 Route 234 south - Prince William Parkway/Manassas/Dumfries begin Route 234 concurrency
• Exit 47 Route 234 north/Business Route 234 - Manassas/Manassas National Battlefield Park end Route 234 concurrency
• Exit 52 US 29 - Centreville
• Exit 53 Route 28 - Dulles Airport/Centreville
• Exit 55 Route 7100 - Fairfax County Parkway/Springfield/Reston/Herndon
• Exit 57 US 50 - Fairfax/Fair Oaks/Winchester
• Exit 60 Route 123 - Fairfax/Vienna
• Exit 62 Route 243 - Nutley Street/Vienna/Fairfax
• Exit 64A I-495 south - Richmond
• Exit 64B I-495 north - [Baltimore, Maryland|Baltimore]] eastbound only
• I-495 eastbound left exit only, HOV-2 during rush hour
• Exit 66 Route 7 - Leesburg Pike/Falls Church/Tysons Corner
• Exit 67 (Route 267) - Dulles Airport/to I-495 north/Baltimore westbound only
• Exit 68 Westmoreland Street eastbound only
• Exit 69 US 29/Route 237 - Washington Boulevard/Lee Highway eastbound only
• Exit 69 Sycamore Street/Falls Church westbound only
• Exit 71 Route 120/Route 237 - Glebe Road/Fairfax Drive eastbound only
• Exit 71 Route 120 - Glebe Road westbound only
• Exit 72 US 29 - Lee Highway/Spout Run Parkway eastbound only
• Exit 73 US 29 - Lee Highway/Rosslyn/Key Bridge
• Exit 75 Route 110 south - Pentagon/Alexandria eastbound only

Virginia/DC line

• US 50 west/Arlington Boulevard/George Washington Memorial Parkway westbound exit/eastbound entrance begin US 50 concurrency

Note: The Independence Avenue and E Street exits are in the opposite order going westbound.

• Independence Avenue left exit and entrance westbound, left entrance eastbound
• US 50 east/Constitution Avenue - Downtown eastbound exit/westbound left entrance end US 50 concurrency
• E Street all trucks must exit westbound, left exit and entrance westbound
• Rock Creek Parkway eastbound left exit/westbound entrance
• Pennsylvania Avenue eastbound exit/westbound entrance
• merges with Whitehurst Freeway (US 29) towards Canal Road

Spur Routes

None, although Interstate 266 was planned in northern Virginia and Washington, D.C. It was cancelled due to environmental causes.

Notes

• This is the only 2 digit Interstate to enter the District of Columbia (other than the 100 yards (91 m) or so that I-95 passes through DC on the Woodrow Wilson Bridge). I-66 was planned to intersect I-95, before I-95 was rerouted to the east side of the Capital Beltway.

• The U.S. Department of Transportation has had plans to extend I-66 westward across the country to California. Highway mavens have speculated as to where I-66 would go, such as the Corridor H Freeway in West Virginia and United States Highway 400 in Kansas.

• Former Governor Paul Patton has written I-66 into law in Kentucky, with the routing being confirmed along the state's Daniel Boone and Louie B. Nunn (formerly Cumberland) Parkways. Preliminary construction has started on a segment in Pulaski county.