Decatur County was organized in 1850 and named for Stephen Decatur, a naval hero of the War of 1812. An area for the county seat was selected by the county commissioners and named it Decatur. The public objected, and prevailed upon the General Assembly to order a vote to establish a county seat. The majority vote in 1853 favored moving the county seat a few miles to the east and naming it Independence.
Citizens of Decatur refused to relinquish the county records, so the records were taken under cover of darkness to Independence with a wagon and a team of oxen. Later it was discovered that there was another town by the same name in Buchanan County. Decatur County then changed its county seat’s name to South Independence. In 1855, the name was changed to Leon.
The first courthouse was 20 by 22 feet and 14 feet high, made of logs and cost $375 in 1851. After only a few years, the crude log structure was outgrown and a new courthouse built to replace it. A new one was begun but a windstorm destroyed it before it could be finished. The next was razed by a fire on March 31, 1874.
After the misfortune of the previous courthouses, the people of the county were determined to build one which would stand more than a few years. Consequently, in 1875, at an approximate cost of $20,000, a brick courthouse was completed. Voters passed a resolution to build another courthouse in 1905. This time the courthouse was built of iron, steel, stone, tile, brick, marble and granite – completely fireproof and a safe place to keep valuable records. The structure, still in use today, was dedicated in 1908 and cost $70,000.