The Interstate begins at a point along the four-lane US 87 freeway south of downtown Lubbock. Mile 0 is posted near 77th Street, about five blocks south of Loop 289. Exit numbering begins just to the south, with exit 1 at the 82nd Street interchange; the freeway becomes six lanes at its north end. The Loop 289 interchange is a cloverleaf between the one-way frontage roads of each highway, and with direct ramps from I-27 south to Loop 289 west (exit 1A) and Loop 289 east to I-27 north. U.S. Highway 84 (Avenue Q and Slaton Highway) crosses I-27 at a three-level diamond interchange, with an extra approach from the northeast carrying Avenue A (former U.S. Highway 87 Business) into the junction. Exit 1B connects I-27 south to US 84 and the Loop 289 frontage roads, while all traffic from US 87 north to US 84, US 87 Business, or Loop 289 must use exit 1 for 82nd Street.