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
Added three photos covering I-670 east at I-70 and U.S. 24/40/71 in Kansas City, Missouri from July 13, 2026.
2026-08-28 16:20:24
Added photos of the south end from I-35 north taken on July 13, 2026 and of the north end from I-29/U.S. 71 north from July 14, 2026. Also added scan of Kansas City from the 1967 Kansas Official Highway Map.
2026-08-28 15:55:18
Added/replaced photos at the south junction from I-35 northbound from 07/13/26 and added two photos at the north junction from I-35 southbound shot on 07/14/26.
2026-08-28 15:01:12
Added photos showing new signage installed at the south end of Interstate 229 from July 14, 2026. The urban loop is on borrowed time, as MoDOT is progressing on the I-229 Moving Forward project, which despite the name, calls for the decertification of the entire Interstate designation. Construction removing the Double-Decker Bridge by Downtown St. Joseph and replacing it with an at-grade arterial is anticipated from 2028 to 2030.
2026-08-28 14:25:51