See Full Constitution
Section 63. Area of counties -- Boundaries -- Creation and abolishment of counties.
No new county shall be created by the General Assembly which will reduce the county or counties, or either of them, from which it shall be taken, to less area than four hundred square miles; nor shall any county be formed of less area; nor shall any boundary line thereof pass within less than ten miles of any county seat of the county or counties proposed to be divided. Nothing contained herein shall prevent the General Assembly from abolishing any county.