Interstate 35 (I-35) is a north–south Interstate Highway in the central United States. I-35 stretches from Laredo, Texas, on the U.S.-Mexico border to Duluth, Minnesota, at Minnesota Highway 61 (London Road) and 26th Avenue East. Many interstates used to have splits or spurs indicated with suffixed letters (N/S/E/W), but I-35 is the only one that still has such divisions. In two stretches, both through twin cities, the highway splits into Interstate 35E (Dallas and St. Paul) and Interstate 35W (Fort Worth and Minneapolis).

Interstate 35 does not directly connect to either international border. I-35's southern terminus is a traffic signal in Laredo, Texas, just short of the United States-Mexico border. Travelers going south can take one of two toll bridges across the Rio Grande and the Mexican border—straight ahead into Juarez-Lincoln International Bridge, or via Interstate 35 Business through downtown Laredo into Gateway to the Americas International Bridge. To the north, I-35 terminates in Duluth, Minnesota, with connections to Canada from the interstate's terminus via Minnesota Highway 61 to Grand Portage, or north to the border at International Falls by U.S. Route 53 in Duluth, but that route is more typically accessed from the south by Minnesota Highway 33 at Cloquet.