Business Loop I-35 - Round Rock

Business Loop I-35L formerly branched east from IH 35 along Mays Street (old U.S. 81) through the Round Rock city center. The 3.65 mile long route was established in a mileage transfer from State Loop 384 on June 21, 1990. It began at a diamond interchange (Exit 250) and ended at a half diamond interchange (Exit 254) with Old Settlers Boulevard (FM 3406).

Mays Street south of U.S. 79 was transferred to the city of Round Rock on February 28, 2013. This action coincided with the cancellation of Business Loop I-35L and redesignation of the northernmost 1.4 miles as State Spur 379.

Additionally alignment changes were made at both ends of the old business route. The south end was reconfigured during work to build the adjacent interchange with SH 45 North, an east-west toll road, while Mays Street was realigned to the north to no longer end directly across from FM 3406 and the on-ramp to IH 35 north.