As of the 2010 Census, the population of the county was 916,924, White Americans made up 77.9% of Dupage County's population; non-Hispanic whites represented 70.5% of the population. Black Americans made up 4.6% of the population. Native Americans made up 0.3% of Dupage County's population. Asian Americans made up 10.1% of the population (4.5% Indian, 1.6% Filipino, 1.4% Chinese, 0.7% Pakistani, 0.5% Korean, 0.4% Vietnamese, and 0.1% Japanese). Pacific Islander Americans made up just 0.0% of the population. Individuals from other races made up 4.9% of the population; people from two or more races made up 2.2% of the county's population. Hispanics and Latinos (of any race) made up 13.3% of Dupage County's population.
As of the 2000 United States Census, there were 904,161 people, 325,601 households and 234,432 families residing in the county. The population density was 2,710 inhabitants per square mile (1,050 /km2). There were 335,621 housing units, at an average density of 1,006 inhabitants per square mile (388 /km2). The racial makeup of the county was 84.05% White, 3.05% Black or African American, 0.17% Native American, 7.88% Asian, 0.02% Pacific Islander, 3.12% from other races and 1.71% from two or more races. 9.00% of the population is Hispanic or Latino of any race. 17.3% were of German, 11.8% Irish, 11.0% Italian, 9.8% Poles and 5.1% English ancestry according to the Census. 79.3% spoke English, 7.7% Spanish, 1.5% Polish and 1.2% Tagalog as their first language.
There were 325,601 households, out of which 37.00% had children under the age of 18 living with them, 60.90% were married couples living together, 7.90% had a female householder with no husband present and 28.00% were non-families. 22.90% of all households were made up of individuals and 6.80% had someone living alone who was 65 years of age or older. The average household size was 2.73 and the average family size was 3.27.
In the county, the population was spread out with 26.70% under the age of 18, 8.20% from 18 to 24, 32.40% from 25 to 44, 22.80% from 45 to 64 and 9.80% who were 65 years of age or older. The median age was 35 years. For every 100 females, there were 97.20 males. For every 100 females, age 18 and over, there were 94.20 males.
The median income for a household in the county was $77,441 and the median income for a family was $93,086. Males had a median income of $60,909 versus $41,346 for females. The mean or average income for a family in DuPage County is $121,009, according to the 2005 census. The per capita income for the county was $38,458. About 2.40% of families and 3.60% of the population were below the poverty line, including 3.90% of those under age 18 and 4.30% of those age 65 or over.
