Interstate 55 (abbreviated I-55) is an interstate highway in the central United States. Like other interstates, it is commonly referred to as I-55. Its odd number indicates that it is primarily a north-south highway. It goes from Laplace, Louisiana (some 25 miles (40 km) west of New Orleans) at Interstate 10 to Chicago at U.S. Route 41 (Lake Shore Drive), at McCormick Place.

The section of Interstate 55 between Chicago and St. Louis was built as a bypass for U.S. Highway 66.

Interstate 55 is the only Interstate highway that crosses the Mississippi River twice - once at Memphis, Tennessee, and then again at St. Louis, Missouri.

I-55 map