 When area code 316 covered all of southern Kansas, the boundary ran from west to east roughly following a path along K-4 and K-96.The code boundary dipped along I-135 in McPherson County and continued east to just north of Emporia in Lyon County along the Kansas Turnpike, and ended at the Missouri state line.With the area code now shrunken to a fraction of its former size, 316 is the only one of Kansas' four area codes that does not reach the Missouri border.