List of Interstate Highways
There are 70 primary Interstate Highways in the Interstate Highway System, a network of controlled-access freeways in the United States. They are assigned one- or two-digit route numbers, whereas their associated "auxiliary" Interstate Highways receive three-digit route numbers. Typically, odd-numbered Interstates run south-north, with lower numbers in the west and higher numbers in the east; even-numbered Interstates run west-east, with lower numbers in the south and higher numbers in the north. Highways whose route numbers are divisible by "5" usually represent major coast-to-coast or border-to-border routes (ex. I-10 travels from Santa Monica, California, to Jacksonville, Florida, traveling from the Pacific to Atlantic oceans). Additionally, auxiliary highways have their numbering system where a different number prefixes the number of its parent highway.
Southern Illinois
Southern Illinois has 4 major interstate freeways that connect with Missouri, Indiana, and Kentucky. Depending on the definition of Little Egypt's boundaries, there are four interstates in the region. I-57 is the main north-south freeway through Southern Illinois. It runs through the center of the area. South of Marion is the western terminus of I-24. It runs southeast, crossing into Paducah, Kentucky near Metropolis. South of its junction with I-24, I-57 bends to the southwest and crosses into Missouri near Illinois' southernmost point by Cairo. I-70 runs east-west from St. Louis to central Indiana. I-64 runs east-west from St. Louis to southern Indiana. It is cosigned with I-57 for a short stretch at Mt. Vernon. I-57 is responsible for much of the growth found around the city of Marion.Bridges and ferries are an important feature in the region, being it is surrounded on three sides by major rivers, the Ohio and Wabash rivers to the east and south, and the Mississippi River to the west.
Indiana: