Interstate 35 (abbreviated I-35 or IH-35) in Texas is a major north–south Interstate Highway running from Laredo near the United States-Mexico border to the Red River north of Gainesville where it crosses into Oklahoma. Along its route, it passes through the cities of San Antonio, Austin, and Waco before it splits into two auxiliary routes just north of Hillsboro. Interstate 35E heads northeast where it passes through Dallas. Interstate 35W turns northwest to run through Fort Worth.