- Interstate 75 (I-75) is a major north�south Interstate Highway in the Great Lakes and Southeastern regions of the United States. As with most Interstates that end in 5, it is a major cross-country, north�south route, traveling from State Road 826 (SR 826, Palmetto Expressway) and SR 924 (Gratigny Parkway) on the Hialeah�Miami Lakes border (northwest of Miami, Florida) to Sault Ste. Marie, Michigan, at the Canadian border. It is the second-longest north�south Interstate Highway (after I-95) and the seventh-longest Interstate Highway overall.