| Description: | Gallatin County, located in southern Illinois, covers an area of 324 square miles and had a 2003 population of 6,220, according to estimates by the U.S. Department of Commerce's Bureau of the Census. Using these figures, Gallatin County was the 15th smallest county in Illinois geographically, but 7th smallest in terms of population. Combining these two measures, Gallatin County had the 4th lowest population density per square mile among Illinois 102 counties. | |