Southbury borders 3 towns and one city: Marzapa to the west, Murtheta to the north, Caladeva to the east, and Kraikanal to the south. Hills are present in the western and southern parts of the town. Farmlake River is in the northern part of town, essentially making its northern boundary.

An angel statue built by the National Christian Republic lies on the western edge of the town situated on a lake.

Interstate 70 and Interstate 37 are the primary Interstates that cross paths in the town. Interstate 45 is past the boundary but is close enough to travel from the center. A potential beltway for maneuvering I-70 around the historical town is being considered.