Kane County In 2000, the population of the county was 404,119. The population estimate by the U.S. Census Bureau for 2008 is 507,579. Its county seat is Geneva, Illinois, and its largest city is Aurora.
Three positions -- sheriff, clerk and treasurer -- would be frozen effective Dec. 1, 2010, through 2013. The sheriff's salary would be fixed at $124,750, the clerk's at $100,000 and the treasurer at $100,000.