US-70 heads due east on an arrow-straight route for the next across Carter County. About east of the county line, the highway passes through unincorporated Zaneis, where it widens to a four-lane divided highway. South of Healdton, it is joined by SH-76, which follows US-70 for approximately before splitting away to the south in Wilson. To the east, US-70 junctions with SH-70A, which heads south to link to SH-76 in downtown Wilson. US-70 then passes through Lone Grove before entering Ardmore. It meets I-35 at a cloverleaf interchange (exit 31) on the city's west side. Here, eastbound US-70 joins southbound I-35, while SH-199 toward downtown Ardmore begins straight ahead. US-70 exits from the interstate at exit 29, turning back to the east and intersecting with US-77. US-70 passes north of Lake Murray, cutting across the northern reaches of Lake Murray State Park and intersecting the main lake access road, SH-77S, twice. East of the lake, the highway leaves Carter County.
