sentences:  It was formed from unorganized territory near Pike County on January 13, 1825.Although the county had been created, its government was not organized for several years; for administration purposes it was attached first to Schuyler County (until 1826), then to Peoria (until 1831), and finally to Warren County.The organization of the county government was finally completed in 1835, after a large influx of settlers following the Black Hawk War.