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Illinois · Chicago Western Suburbs · #61 Most Populous County in the US
DuPage County, Illinois
The wealthiest major suburban county in Illinois, west of Chicago along the I-88 corridor. Property tax, courts, public records, probate, and senior services for DuPage County residents.
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Tell us your goal and we'll guide you step-by-step to the right office, forms, and official resources.
DuPage County's assessment ratio means effective tax rates are low — but incorrect appraisals still cost money. Ownwell manages the appeal with no upfront cost.
Office: DuPage County Sheriff’s Office – 501 N. County Farm Road, Wheaton, IL 60187 | (630) 407-2400 (open 24 hours) | Non-emergency (630) 682-7256 | General business (630) 407-2000 | Warrants (630) 407-2290; Sheriff James Mendrick.
Notes: For an active emergency, call 911. DuPage County’s population is roughly 932,877, making it one of Illinois’s most populous counties, located about 25 miles west of Chicago.
Roads & Utilities
ROADS & TRANSPORTATION
Roads: I-88, I-355, I-290, and I-294 serve Wheaton, the county seat; Naperville is the county’s largest city.
Notes: DuPage County was formed February 9, 1839, from Cook County, named for the DuPage River, itself named for a French fur trapper who settled along the stream before 1800. The first European-American settlers arrived in 1832; the local Potawatomi population was forced out the following year after ceding their land in the 1833 Treaty of Chicago, part of the broader Indian Removal era that sent Indiana and Illinois Potawatomi on the 660-mile Trail of Death.
Business & Permits
BUILDING & PERMITS
Office: DuPage County Administration Building – 421 N. County Farm Road, Wheaton, IL | (630) 407-5500 (County Clerk) | (630) 407-5400 (Recorder). DuPage County Judicial Center – 505 N. County Farm Road, Wheaton, IL | (630) 407-8700 (Circuit Clerk).
Notes: Naperville, the original county seat, lost that status in a fiercely contested 1867 referendum – Wheaton won by a narrow margin of 1,686 to 1,635, after the Wheaton brothers campaigned hard and offered free land for a new courthouse. In a genuinely dramatic aftermath, Naperville initially refused to turn over county records, prompting a group of Civil War veterans to conduct what became known as a “Midnight Raid” on the Naperville courthouse to retrieve them. Wheaton itself grew around a railroad depot sign posted by workers in the 1830s-40s; founder Warren Wheaton served as the village’s first president after its 1859 incorporation and donated land that became Wheaton College.
Veterans Services
VETERANS SERVICES
Office: DuPage County Veterans Assistance Commission – confirm current contact via dupagecounty.gov.
Libraries
LIBRARIES
Wheaton Public Library / Naperville Public Library (multiple locations) – confirm current addresses/phones via the county library system.
Parks & Recreation
PARKS & RECREATION
Key Assets: The Wheaton College campus, the Forest Preserve District of DuPage County (including Warrenville Grove and Dunham Forest Preserve’s restored tallgrass prairie), and historic downtown Naperville and Wheaton are the county’s premier heritage and recreational attractions.
Notes: The genuine, dramatic 1867 “Midnight Raid” on the Naperville courthouse – following the contested county-seat vote – is among the standout local historical facts covered in this project.
GIS & Maps
GIS & MAPS
Appraisal/Parcel Search: DuPage County Assessor’s Office – confirm current contact via dupagecounty.gov.
Animal Services
ANIMAL SERVICES
DuPage County Animal Care and Control – confirm current contact via dupagecounty.gov.
Environmental & Waste
ENVIRONMENTAL / WASTE MANAGEMENT
Office: DuPage County Department of Environment – confirm current contact via dupagecounty.gov.
NOTES: DuPage County is the twenty-second county completed in Illinois’s Round 3 v2 redo, under the A+ sourced standard established for this project. The genuine, dramatic 1867 “Midnight Raid” on the Naperville courthouse is among the standout local historical facts covered in this project. All contact information above was sourced via web search as of early August 2026 and should be reconfirmed directly with the relevant office before a visit, deadline-sensitive filing, or emergency-adjacent decision.
About DuPage County
DuPage County is Chicago’s most affluent western suburb – Fermilab’s world-leading particle physics research, Morton Arboretum’s 1,700-acre tree museum, and the Fox River corridor of historic communities define a county whose combination of natural assets, educational institutions, and suburban prosperity makes it one of the most desirable counties in the Midwest.
Wheaton (the county seat, population ~53,000) is DuPage County’s governmental hub, a western Chicago suburb whose Wheaton College campus, historic downtown, and County Complex anchor the governmental center of Illinois’s wealthiest suburban county.
All Services
Browse every category and topic available for this county.
DuPage County Supervisor of Assessments at 421 N. County Farm Road, Wheaton, IL 60187, phone 630-407-5858. IL assessed at 33.33% of market value.
Recommended
DuPage County's 2.16% effective rate is more than double the national average. The 2025 levy increased bills by 3.83%. Appeal deadlines vary by township. Ownwell manages the process - no upfront cost, you pay only if you save.
Courts & Legal
DuPage County Circuit Court at 505 N. County Farm Road, Wheaton, IL 60187, phone 630-407-8700, handles probate.
Marriage & Vital Records
Marriage licenses, divorce records, and birth & death certificates are handled by the following office(s):
COUNTY CLERK (Records, Vital Records, Elections)
421 N. County Farm Rd., Wheaton, IL 60187
(630) 407-5500
CIRCUIT CLERK (Court Records, Marriage Licenses)
505 N. County Farm Rd., Wheaton, IL 60187
(630) 407-8700
ELECTIONS (County Clerk)
421 N. County Farm Rd., Wheaton, IL 60187
(630) 407-5600
Genealogy
County-level record sources
DuPage County Circuit Clerk (probate/estate case files – see Probate section above).
DuPage County Historical Museum, Wheaton – local historical resource for the county.
Local societies
No dedicated DuPage County genealogical society was confirmed in available directories.
Probate & Estate
Losing someone and having to deal with courts and paperwork at the same time is hard. This section won’t make that easier, but it should tell you what to expect, what it costs, and where to go – so at least you’re not walking in blind.
Where to go
DuPage County Circuit Clerk (18th Judicial Circuit) 505 North County Farm Road, Wheaton, IL 60187 (630) 407-8700
DuPage County is the 2nd-most-populous county in Illinois, immediately west of Cook County/Chicago. It is one of only seven single-county judicial circuits in Illinois (along with Cook, Kane, Lake, McHenry, St. Clair, and Will). The county seat, Wheaton, was the site of a notable 1938 trial defended by Clarence Darrow at the historic Old DuPage County Courthouse.
Step 1: figure out which path applies
Illinois has NOT adopted the Uniform Probate Code and is not a community property state – it follows common law property principles. Illinois probate is governed by the Probate Act of 1975 (755 ILCS 5/). Two main paths:
Small Estate Affidavit – for estates where personal property (excluding real estate) is valued at $150,000 or less (raised from $100,000 effective August 15, 2025), with no unresolved debts or claims and no real estate involved. No formal court probate is required.
Formal Probate (Independent or Supervised Administration) – required when the estate doesn’t qualify for the small estate affidavit. Most Illinois probate cases proceed under Independent Administration, letting the estate representative act without prior court approval for most routine actions.
Step 2: filing for formal probate
File the decedent’s original will (if one exists) with the DuPage County Circuit Clerk, where the decedent resided at death.
Petition the court to open the estate and appoint an executor (if there’s a will) or an administrator (if intestate).
The court issues Letters of Office (Letters Testamentary or Letters of Administration) appointing the representative.
Publish notice to creditors and unknown heirs as required by Illinois law.
Under Independent Administration, the representative marshals assets, pays valid debts and taxes, and distributes the remaining estate without needing court approval for each step.
File a final accounting or closing documents to formally close the estate.
What it costs
Illinois imposes its own state estate tax on estates valued above $4 million, with rates up to 16%. There is no Illinois inheritance tax.
Filing fees vary by county – confirm current amounts with the DuPage County Circuit Clerk.
Most uncontested probate proceedings in Illinois can be completed within about a year.
Probate filings, estate administration, and guardianship matters are handled by the following office(s):
Public Safety & Arrests
Arrest records, inmate search, and law enforcement services are handled by the following office(s):
SHERIFF
501 N. County Farm Rd., Wheaton, IL 60187
(630) 407-2000
Elections & Voting
Voter registration, polling locations, and elections information are handled by the following office(s):
COUNTY CLERK (Records, Vital Records, Elections)
421 N. County Farm Rd., Wheaton, IL 60187
(630) 407-5500
ELECTIONS (County Clerk)
421 N. County Farm Rd., Wheaton, IL 60187
(630) 407-5600
Health & Human Services
Offices & Contacts
Health services, social services, and assistance programs are handled by the following office(s):
Du Page County Health Dept
(630) 682-7400
IL DCFS — Wheaton
(630) 682-7030
IL Medicaid
(800) 843-6154
Advocate Good Samaritan Hospital (Downers Grove)
advocatehealth.com
Northwestern Medicine Central DuPage Hospital (Winfield)
nm.org/central-dupage
Edward Hospital (Naperville)
eehealth.org
Rush Copley Medical Center (Aurora)
rushcopley.com
Public Health Information
PUBLIC HEALTH
Office: DuPage County Health Department – confirm current contact via dupagecounty.gov.
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