US Route 12 hugs the southern shore of Lake Michigan, trying to cut through northwestern Indiana to get from Chicago to the state of Michigan in the most efficient way possible. It's the northernmost east-west surface highway for most of its length. US Route 12 enters Indiana from Chicago, Illinois, in the very northwest corner of Indiana, concurrent with US Route 20 and US Route 41. US Route 12 soon splits from those routes through the industrial areas of Whiting and East Chicago. US Route 12 then passes through Gary and past the entryway to Indiana Dunes National Park, before crossing through Michigan City and leaving Indiana into the very southwest corner of Michigan.