Route 12 goes through the following towns: Groton, Ledyard, Preston, Norwich, Lisbon, Griswold, Canterbury (0.14 miles only), Plainfield, Killingly, Putnam, and Thompson.
Route 12 travels through the following towns: Groton, Ledyard, Preston, Norwich, Lisbon, Griswold, Canterbury (a short stretch only), Plainfield, Killingly, Putnam, and Thompson.