Yorkville (Official name:
United City of Yorkville) is a city located in
Kendall County,
Illinois,
United States. The population was 6,189 at the
2000 United States Census and had grown to 16,921 . It is the
county seat of Kendall County. Yorkville is located in the center of Kendall County, the fastest-growing county in Illinois and is the fastest-growing county in the United States.