Highway History
- http://www.fhwa.dot.gov/infrastructure/history.htm
- United States Federal Highway Administration page with a collection of various auto trail, U.S. highway, and Interstates histories, some from older FHWA publications, as well as other related information.
National Road Association of Illinois
- http://www.nationalroad.org/
- Organization focused on promoting the history of the first byway going west across America, currently known as U.S. Route 40. Includes history of the road, stories, membership details, and contacts.
US-27 in Michigan
- http://www.cqql.net/us-27.htm
- Includes some historic photographs and details about this route's former routing in the state, now supplanted primarily by US-127 and Interstate 69.