I-375 and the Chrysler Freeway begin at Jefferson Avenue between St. Antoine Street and Beaubien Street in downtown Detroit near the Renaissance Center. They run east before turning north. Just about a mile (1.6 km) after the southern terminus, I-375 meets the Fisher Freeway which carries I-75 north of downtown. At this interchange, I-75 takes ramps to leave the Fisher Freeway and use the Chrysler Freeway, replacing I-375. I-375 is a four-lane freeway south of the I-75 interchange, where it widens to six lanes. The entire length of I-375 is included on the National Highway System, a network of roadways that are important to the country's economy, defense, and mobility.