Libertyville is an affluent northern suburb of Chicago in Lake County, Illinois, United States. It is located 5 miles (8 km) west of Lake Michigan on the Des Plaines River. The 2010 census population was 20,315. (There is also a township of the same name, which includes the village and some surrounding areas.) Located in northeastern Illinois, southwest of Waukegan and west of Lake Forest, its immediate neighbors are Mundelein to the west, Green Oaks, Mettawa, and Rondout to the east, Gurnee to the north, Grayslake to the northwest, and Vernon Hills to the south.
As of the census of 2000, there were 20,742 people, 7,298 households, and 5,451 families residing in the village. The population density was 2,364.5 people per square mile (913.2/km²). There were 7,458 housing units at an average density of 850.2 per square mile (328.3/km²). The racial makeup of the village was 92% White, 5% Asian and 1% African American. 0.1% is Native American. About 1% each are classified as belonging to other races or to two or more races. 3% of the population were Hispanic or of any race. While still largely homogeneous, ethnic diversity has increased slightly since the 1960 census, when the population was indicated as being 99.9% white.

As of the 2000 census, there were 7,298 households, out of which 40% had children under the age of 18 living with them, 66% were married couples living together, 7% had a female householder with no husband present, and 25% were non-families. 22% of all households were made up of individuals and 8% had someone living alone who was 65 years of age or older. The average household size was 2.7 and the average family size was 3.2.

28% of the village's population is under the age of 18, 5% from 18 to 24, 27% from 25 to 44, 28% from 45 to 64, and 12% 65 years of age or older. The median age is 39 years. For every 100 females there were 92.9 males. For every 100 females age 18 and over, there were 86.9 males.

According to a 2007 estimate, the median household income was $106,337, and the median income for a family was $127,474. Males had a median income of $72,320 versus $39,455 for females. The per capita income for the village was $40,426. About 1.9% of families and 3.5% of the population were below the poverty line, including 4.2% of those under age 18 and 4.9% of those age 65 or over.