I-35 splits up into I-35W and I-35E in the Dallas/Fort Worth, Texas area. The official mile markers follow I-35E through Dallas -- I-35W, which is 85 miles in length, carries its own mileage from Hillsboro to Denton, as though it were an x35 loop.
I-135, which branches off in Wichita, Kansas, is 95 miles (153 km) long. It carried the designation I-35W until the 1980s, despite never rejoining the main line of I-35. It terminates in Salina, Kansas at the intersection with Interstate 70 (though the controlled-access freeway continues north as US 81).
At Medford, Minnesota, the on/off ramps lead to roundabouts rather than standard cross intersections. This is the first site in the state linked to a major highway to use roundabouts.
Interstate 335 was planned as an additional bypass of the Twin Cities; that road was never built.
I-35 splits again into I-35W and I-35E in the Minneapolis/Saint Paul, Minnesota area. At one sharp turn in I-35W near the junction with I-94, it is advised to slow to 35 mi/h (56 km/h) (although many drivers are able to maintain the speed limit of 55 mi/h (88 km/h)). Additionally, it is not possible to go from westbound I-94 to northbound I-35W or from southbound I-35W to eastbound I-94 without resorting to surface streets.