It runs northward through residential areas before skirting the Cranston Country Club.

It continues north, passes over I-295 without an exit, and ends at Route 12 in Cranston.

Route 51 is the only Rhode Island state highway that does not have any state-maintained sections.

Generally, maps which show Route 51 at all show it starting at Route 37 on Natick Avenue, then heading along Natick Avenue and Phenix Avenue, ending at Route 12.

According to RIDOT, the towns through which Route 51 runs requested that the signs be removed to give them time to prepare for the increase in traffic brought by a numbered route.