County History
Leon County was formed in 1846 and Centerville has been county seat since 1851
Leon County was carved out of Robertson County in 1846, and Centerville replaced Leona as county seat in 1851 because the law required the seat to be near the county's geographic center.
The Texas Legislature created Leon County from Robertson County in 1846. The first county court met that October with R. E. B. Baylor presiding. The original county seat, Leona, was not centrally located, so Centerville was platted in 1850 and took over as county seat by 1851. State law required county offices to sit near the geographic center — hence the name Centerville.
The county covers about 1,078 square miles in East Texas. The Trinity River forms its eastern boundary. The county's economy shifted over the decades from cotton and corn to livestock, timber, and oil production. Interstate 45 now runs through Centerville, connecting it to Dallas to the north and Houston to the south. For deeper history, the Texas State Historical Association's Handbook of Texas has detailed entries on Leon County and Centerville.
Source to confirm: Handbook of Texas — Leon County