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[?].
77
None, although I-266 was planned in Washington, D.C., but was cancelled. It was cancelled due to environmental causes.
This is the only 2 digit Interstate to enter DC (unless you count the 100 yards or so that I-95 crosses over the DC section of the
Potomac). I-66 used to intersect I-95, before they rerouted I-95 to be the east side of the Capitol Beltway.
The Department of Transportation has 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.
President George W. Bush has written I-66 into law in Kentucky, with the routing being confirmed along the state's Daniel Boone and Cumberland (Louie B. Nunn) Parkways.