Peoria County was separate from Tazewell in both 1830 and 1840 censuses. However, Tazewell was much larger than it is today. It took in all or parts of 11 of today's counties in 1830, and shrunk to all of Tazewell and parts of Woodford and Mason County by 1840. It came to present boundaries by 1850 census. Margie Bridges