Somerville is in Section 3 at the northern end of Milford Township on the Preble County line. The village was laid out Oct. 7, 1831, by Jacob F. Rowe.
A post office, known as Williams' Store, was created March 10, 18919, and changed Feb. 28, 1834, to Somerville. It was a stop on the Hamilton & Eaton Railroad (later the Pennsylvania, Conrail and Norfolk & Southern). The name sometimes has been spelled Summerville and Sommerville.