Smithsonian

Sign along Highway 40

In this 1956 photo, officials stand in front of the sign marking the beginning of construction of Missouri’s new interstate highways. According to interstate historian Richard F. Weingroff, Missouri, Kansas, and Pennsylvania can share claim to the “first” part of the Interstate Highway System, depending how “first” is defined. Missouri awarded the first contract using the new interstate funding. Kansas had already awarded a contract with state money before the signing of the federal funding act. The Pennsylvania Turnpike, which became part of the Interstate Highway System, opened almost sixteen years before the Federal Aid Act of 1956.

Credit: Missouri Department of Transportation.