DuPage County, Illinois

DuPage County, Illinois
County	DuPage County
State	Illinois
Founded	1839
Seat	Wheaton
Largest city	Naperville
Area total sq mi	336
Area land sq mi	327
Area water sq mi	8.7
Population as of	2020
Population total	932,877
Population density sq mi	2852
Time zone	Central
Web	www.dupageco.org
Named for	DuPage River

DuPage County, Illinois is a county located in the northeastern part of the U.S. state of Illinois. As part of the Chicago metropolitan area, it is the second-most populous county in the state, trailing only Cook County. The county seat is Wheaton, and its largest city is Naperville. Known for its affluent communities, strong economy, and extensive park districts, DuPage County is a major hub for commerce, research, and education within the Midwestern United States.

History

The region was originally inhabited by the Potawatomi people before European settlement. Following the Black Hawk War and subsequent treaties like the Treaty of Chicago, the area was opened for development. The county was officially formed in 1839 from Cook County and named for the DuPage River. Early settlers included Joseph Naper, who founded Naperville, and the county saw significant growth with the arrival of the Galena and Chicago Union Railroad. The establishment of institutions like Wheaton College and the Fermi National Accelerator Laboratory in nearby Batavia marked its development into a center for education and science. The Argonne National Laboratory, managed by the University of Chicago, also became a key federal research facility in the region.

Geography

According to the U.S. Census Bureau, the county has a total area of 336 square miles, of which 327 square miles is land and 8.7 square miles is water. Major waterways include the DuPage River, Salt Creek, and East Branch DuPage River. The topography is characterized by gentle prairie and woodland, with significant forest preserves managed by the Forest Preserve District of DuPage County. It is bordered by Cook County to the east, Will County to the south, Kane County to the west, and Lake County to the north. Notable natural areas include the Morton Arboretum in Lisle and Herrick Lake Forest Preserve.

Demographics

As of the 2020 United States Census, the population was 932,877, making it one of the most populous counties in the United States. The racial makeup was predominantly Non-Hispanic White, with significant and growing Asian American and Hispanic communities. The county consistently ranks among the wealthiest in the nation by median household income, with high educational attainment levels; a large percentage of residents hold a bachelor's degree or higher. Major municipalities contributing to this diversity include Naperville, Aurora, Downers Grove, and Elmhurst.

Economy

DuPage County has a diverse and robust economy, serving as a major corporate and research corridor. It is home to the Illinois Research and Development Corridor and hosts headquarters for global corporations like Lisle-based Navistar International and Oak Brook-based McDonald's. The Oakbrook Center mall is a premier retail destination. The presence of Fermi National Accelerator Laboratory and Argonne National Laboratory anchors a strong technology and science sector. Other significant employers include Advocate Health Care, Alight Solutions, and Chamberlain Group. The Chicago Mercantile Exchange also maintains operations in the county.

Government and politics

DuPage County operates under a county board system, with an elected County Board Chairman. Historically a Republican stronghold, exemplified by figures like former House Speaker Dennis Hastert, the county has trended towards competitive Democratic performance in recent national elections. It is part of multiple congressional districts, including those represented by Sean Casten and Lauren Underwood. Local municipalities like Naperville and Wheaton have their own mayor–council government systems.

Education

The county is served by numerous high-performing public school districts, including Naperville Community Unit School District 203, Indian Prairie School District 204, and Community High School District 99. Higher education institutions include Wheaton College, a prominent Christian liberal arts college, the College of DuPage—one of the largest community colleges in the United States—and Benedictine University in Lisle. The Illinois Institute of Technology also has a campus in Wheaton. These institutions contribute to the county's highly educated workforce.

Transportation

Major highways crisscross the county, including the Interstate 88 (Ronald Reagan Memorial Tollway), Interstate 355 (Veterans Memorial Tollway), and Interstate 290 (Eisenhower Expressway). Public transit is provided by Pace suburban buses and the Metra commuter rail system, with lines such as the BNSF Railway Line and Milwaukee District/West Line providing service to Chicago Union Station. Chicago O'Hare International Airport is located just northeast in Cook County, providing extensive air travel access.