Its eastern terminus is at the Pennsylvania state line nearly two miles (3.2 km) east of New Middletown.

Upon crossing the border, SR 630 becomes Pennsylvania Route 317 (PA 317), which continues east to Bessemer.

SR 630 runs entirely within the southeastern quadrant of Mahoning County.

It commences from the signalized intersection of SR 170 and Calla Road in the northwestern corner of New Middletown.

Heading east from there, SR 630 passes amidst a number of homes within the village prior to where it meets Struthers Road.