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 photos covering the new eastern end of Interstate 440 at I-57/U.S. 67-167 in Jacksonville. Also added photos covering the west end of I-440 from July 8, 2024.
2026-08-16 15:02:52
Finished adding photos of the end points for the planned route of Interstate 343 along the Muskogee Turnpike in eastern Oklahoma. I-343 has nothing to do with I-43, but the Oklahoma Transportation Commission nonetheless approved the numbering for the route in 2025. AASHTO approved the application at the Annual Fall 2025 meeting.
2026-08-14 15:13:37
Created a page for the proposed western branch of Interstate 42 between IH 35 in Noble County, Oklahoma and I-49 in Springdale, Arkansas. ArDOT and ODOT applied for the designation to AASHTO on October 5, 2023. Efforts to designate the U.S. 412 corridor as an Interstate go back to legislation introduced by Senators in both states on May 21, 2021. The 42 numbering is based off dropping the one from 412...
2026-08-14 15:09:26
Interstate 644 is the proposed renumbering for the tolled Creek Turnpike around the south and east sides of Tulsa, Oklahoma. The designation was approved by AASHTO at the Fall 2025 meeting of the Route Numbering Committee. Included in this new page are photos covering both ends from 07/11 and 07/12/26.
2026-08-12 17:28:57