Interstate 135 (I-135) is an approximately auxiliary Interstate Highway in central and south-central Kansas, United States. I-135, which is signed as north–south, runs between I-35 and the Kansas Turnpike in Wichita north to I-70, U.S. Highway 40 (US-40), and US-81 in Salina. Except for the first , I-135 overlaps US-81 for almost its entire length. The route also runs through the cities of McPherson, Newton, and Park City.
The highway was designated as Interstate 35W (I-35W) until September 1976, when it was renumbered as I-135 to conform to new AASHTO policies that eliminated most suffixed Interstate Highways. It is currently the longest three-digit spur with an odd first digit in the Interstate System.
Route description
thumb|left|I-135 begins at this exit from the Kansas Turnpike.
thumb|left|the southern end of I-135 from I-135
I-135 begins from the south at exit 42 on the Kansas Turnpike. The exit is signed as I-135/I-235/US-81 for Wichita and Salina. US-81 joins I-135 later at exit 1A (East 47th Street South) and remains concurrent with it for the rest of its length. Less than from the Kansas Turnpike tollbooth, I-235, a loop around the westside of Wichita, branches off the highway at exit 1C. I-135 continues northward from there, running just east of the Wichita downtown area. It reunites with I-235 at exits 11A and 11B at milepost 11 at the loop's other end.
I-135 leaves Wichita and continues northward to Newton where it turns northwest around milemarker 33. The freeway continues in this direction for , returning to a due north course at McPherson.
The stretch of I-135 in Saline County from the Saline–McPherson county line to the highway's terminus at I-70, is designated as the Ben E. Vidricksen Highway, in honor of a state senator who was active in pushing for the highway's enlargement.
thumb|left|I-135 ends at this interchange with I-70; US-81 continues north.
The route ends on the northwest side of Salina, at its intersection at I-70. The road continues as US-81 north of this interchange.