Interstate 35W (I-35W), an Interstate Highway, is the western half of I-35 where it splits to serve the Dallas–Fort Worth metropolitan area. I-35 splits into two branch routes, I-35W and I-35E, at Hillsboro. I-35W runs north for 85.2 miles (137.1 km), carrying its own separate sequence of exit numbers. It runs through Fort Worth before rejoining with I-35E to reform I-35 in Denton. It is the more direct route for long-distance expressway traffic, as is noted on signs on I-35 leading into the I-35W/I-35E splits. During the 1970s, billboards existed on I-35 encouraging travelers to take the faster and shorter I-35W route.

Interstate 35 (I-35) is a major north–south Interstate Highway that runs from Laredo, Texas near the Mexican border to Duluth, Minnesota. In Texas, the highway begins in Laredo and runs north 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 splitting into two branch routes just north of Hillsboro: I-35E heads northeast through Dallas, while I-35W turns northwest to run through Fort Worth. The two branches rejoin in Denton to again form I-35, which continues to the Oklahoma state line. The exit numbers for I-35E maintain the sequence of exit numbers from the southern segment of I-35, and the northern segment of I-35 follows on from the sequence of exit numbers from I-35E. I-35W maintains its own sequence of exit numbers.