Yorkville (officially the United City of Yorkville) is a city in Kendall County, Illinois, United States. The population was 16,921 at the 2010 census and was estimated at 19,388 as of 1 July 2017. It is the county seat of Kendall County.
Yorkville is in northern Kendall County at 41°39′57″N 88°26′31″W / 41.66583°N 88.44194°W / 41.66583; -88.44194 (41.6657190, -88.4419490). It is bordered to the northeast by Montgomery, to the east by Oswego, and to the west by Plano. It is 12 miles (19 km) southwest of Aurora and 47 miles (76 km) southwest of downtown Chicago.
According to the 2010 census, Yorkville has an area of 20.058 square miles (51.95 km), of which 19.97 square miles (51.72 km) (or 99.56%) is land and 0.088 square miles (0.23 km) (or 0.44%) is water. The Fox River flows through downtown Yorkville. The city is in Bristol, Kendall, and Fox townships.
As of the census of 2000, there were 6,189 people, 2,220 households, and 1,665 families residing in the city. The population density was 878.8 inhabitants per square mile (339.3/km). There were 2,291 housing units at an average density of 325.3 per square mile (125.6/km). The racial makeup of the city was 96.99% White, 0.42% African American, 0.19% Native American, 0.39% Asian, 0.05% Pacific Islander, 0.73% from other races, and 1.23% from two or more races. Hispanic or Latino of any race were 2.94% of the population.
There were 2,220 households out of which 42.1% had children under the age of 18 living with them, 62.8% were married couples living together, 8.9% had a female householder with no husband present, and 25.0% were non-families. 20.5% of all households were made up of individuals and 8.6% had someone living alone, who was 65 years of age or older. The average household size was 2.76 and the average family size was 3.22.
In the city, the population was spread out with 30.0% under the age of 18, 7.9% from 18 to 24, 33.6% from 25 to 44, 18.7% from 45 to 64, and 9.8% who were 65 years of age or older. The median age was 33 years. For every 100 females, there were 96.7 males. For every 100 females age 18 and over, there were 91.8 males.
The median income for a household in the city was $60,391, and the median income for a family was $67,521. Males had a median income of $49,120 versus $30,977 for females. The per capita income for the city was $24,514. About 0.4% of families and 1.4% of the population were below the poverty line, including 0.9% of those under age 18 and 3.6% of those age 65 or over.