Somerville is located at 35°14'35" North, 89°20'58" West (35.243333, -89.349722).
According to the United States Census Bureau, the town has a total area of 11.36 mi2 (29.41 km2). 11.17 mi2 (28.94 km2) of it is land and 0.18 mi2 (0.47 km2) of it is covered by water. The total area is 1.60% water.
Somerville is located in the Central Standard Time (CST) timezone, GMT-06:00. It observes Daylight Saving Time (DST).