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.
Interstate 535
I-535 is the shortest Interstate in both Minnesota and Wisconsin. It also is the only Interstate in the two states with no exit numbers. I-535 in Wisconsin is one of the few instances in the United States of a three-digit Interstate Highway entering a state that its parent two-digit Interstate does not enter. Other examples include Interstate 275 near Cincinnati, Ohio, Interstate 287, and Interstate 129.