An original Interstate era sign directing motorists to the Chicago Skyway and the Northwest Indiana Interstate network. Photo taken by Jeff Royston (05/26/12).
It was determined by the city of Chicago that the Chicago Skyway was never formally included in the Interstate Highway System in 1999. As such, trailblazers are posted in lieu of reassurance markers along the toll road.
Oklahoma Veterans Memorial Highway System sign posted at the northbound welcome center near Thackerville. Photo taken 10/10/03.
Interstates are commonly dedicated as war memorial highways throughout the United States. One such designation is the Purple Heart Trail, which originates at a monument in Mt. Vernon, Virginia. Purple Heart Trail routes include I-5 in California, I-35 in Texas and I-95 between Augusta and Holton, Maine.
This list breaks down the Interstate-Guide by states (and the District of Columbia) and includes current, former, future, and unsigned routes. Include is the total Interstate mileage for each state, district, commonwealth.