I55

Interstate 55 (I-55) is a major north-south highway of the U.S. Interstate Highway System. It runs from I-10 in Laplace, Louisiana, in the Greater New Orleans area, to an interchange with I-90 and I-94 in Chicago, Illinois, at the edge of the metropolitan area. The route covers approximately 964 miles (1,550 kilometers) and passes through six states: Louisiana, Mississippi, Tennessee, Arkansas, Missouri, and Illinois. The corridor serves as a principal freight and regional travel route between the Gulf Coast and the Midwest, connecting cities such as Baton Rouge, Jackson (MS), Memphis, St. Louis, and Chicago.

Construction and development began in the late 1950s and continued through the 1960s–1980s, with many segments opened in stages. Since completion, I-55 has seen ongoing maintenance, widening projects, and modernization to handle increasing traffic and weather-related challenges, especially in the lower Mississippi River region.

Because I-55 traverses a broad inland route, it intersects several other major highways, forming many connections for cross-country travel. The highway experiences typical interstate congestion around major metro areas, notably near St. Louis and the Chicago area, and is affected by regional weather and flooding events in the Gulf Coast states.