Since the early 2000s, Interstate Guide has documented America's Interstate Highway System through photography, route histories, business routes, and reference material. The site covers both the familiar and overlooked parts of the national network.
Browse Interstate highways by route number or state, explore historical features and trivia, follow proposed corridors, and discover the stories behind the roads that connect the country.
Explore Interstate Guide
Browse Interstate routes, discover business loops, explore historical features, and follow the continuing evolution of America's highway network.
✓ Mainline Interstates
✓ Auxiliary Routes
✓ Future Interstates
✓ Former Routes
✓ Unsigned Routes
✓ Business Routes
Browse by Route Number
Interstate families and branch routes.
Browse by State
Routes organized geographically.
Business Routes
Former alignments and downtown connectors.
Features
History, trivia and numbering guides.
What's New
Recent additions and updates.
About Interstate Guide
Contributors and project history.
The Interstate Highway System has evolved substantially since the early years of completion. Today the system continues to grow with new corridors developed with Congressional authority, such as I-69 between Texas and Indiana, the completion of I-49 in Arkansas and Louisiana and the southern extension of I-27 from Lubbock to Laredo, Texas. Interstate Guide documents both the original network and the routes added through decades of expansion.
Interstate Guide currently documents:
Interstate Numbering Guide
Numbering guidelines for the Eisenhower Interstate System. Why is there an I-238 but no I-38? Read More →
Proposals and Unbuilt Routes
Previously proposed or suggested long distance and regional Interstate corridors that were never realized or otherwise remain unconstructed. Read More →
Recent Updates
Interstate 777 is a designation promoted by the Carolina Core initiative of the Piedmont Triad Partnership for the freeway along U.S. 421 between I-77 near Hamptonville and I-40 and Salem Parkway in Winston-Salem. The same group successfully advocated for an Interstate designation (I-685) along the U.S. 421 corridor between Greensboro and Sanford.
2026-08-10 11:59:33
Added photos from 07/14/26 covering I-35 north at the West Mixmaster Interchange with I-80/235 in West Des Moines, and from I-35/80 east showing the recently completed Northeast Mixmaster Interchange project upgrades at Interstate 235.
2026-08-10 11:43:17
Added page on the proposed designation of Interstate 435 for the outer belt loop around the Greater Des Moines area between I-35 at West Des Moines and I-80 at Altoona. Legislation for upgrades along the freeway along Iowa 5 and U.S. 65 to Interstate standards was passed by the Iowa House and Senate in 2025. Language for I-435 was recently added to the federal surface transportation bill, which could be passed in early 2027.
2026-08-10 11:41:28
Interstate 344 was approved by AASHTO for the John Kilpatrick Turnpike around Oklahoma City in 2023. Signage finally went up in 2025. Posted photos from July 11, 2026 covering both ends from every direction.
2026-08-07 16:15:18