Warrick County, Indiana: History
Warrick County was formed by statute on March 9, 1813, effective April 30, 1813, from Knox County. Warrick and Gibson counties were both created out of this area of Knox County between the White River and the Ohio River. The boundaries of this area began at the mouth of the Wabash River; then up the Wabash River with the meanders thereof to the mouth of the White River; then up the White River with the meanders thereof to the Forks of the White River; then up White River East Fork to where the line between Sections 20 and 29, Township 1 North, Range 4 West, strikes the same; then with that line to the then Gibson County line; then with that line dividing Gibson and Knox Counties to the Ohio River; then down the Ohio River, to the place of beginning. The original boundary still exists in a series of slants along every north–south county line from Posey to Perry County as well as Crawford County's southernmost border. In Vanderburgh County, Baseline Road runs along the original boundary as well.
The same was divided into two separate and distinct counties, by a line beginning on the Wabash River, known as Rector's Base Line (was surveyed by William Rector on the line between Townships 4 South and 5 South, from New Harmony, Posey County, and Alton, Crawford County, Indiana), and with that line east until it intersects the then Gibson County line and that tract of land falling within the southern division thereof was Warrick County. However, because Gibson County organized a month earlier on April 1, this entire territory fell under Gibson County's jurisdiction. Within Warrick County's original jurisdiction included large portions but not entire portions of Crawford, Perry, Posey, Vanderburgh, and roughly 2/3s of Warrick County's current jurisdiction. Evansville was the original county seat, followed by Yankeetown, Newburgh, and finally Boonville, the current seat.