HAMILTON CO IL is situated in the southeastern portion of Illinois and is bounded on the north by Wayne County, on the east by White County, south by Saline County and on the west by Franklin and Jefferson Counties. It is the form of a rectangular parallelogram, and is twenty-four miles from north to south and eighteen miles from east to west, thus containing 432 square miles or 276480 acres.

Topography The surface of this county is generally rolling and with the exception of two or three small prairies, was originally covered size in the county, the largest being the North Fork of the Saline River, which has its origin in Section 8,Township 6, Range 7 east at the junction of Wheeler's Creek and Lake Creek and runs southerly into Saline County.