The boundary between 785 and area code 620, which covers southern Kansas outside of the Wichita metropolitan area, runs from west to east roughly following a path along K-4 and K-96. The code boundary dips along I-135 in McPherson County and continues east to just north of Emporia in Lyon County along the Kansas Turnpike. At this point, area code 785 reaches its easternmost boundary with the current boundary for area code 913, although a small portion of the northeast corner of Kansas across the Missouri River from St. Joseph, Missouri is part of 785.