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Illinois · Quad Cities · #428
Rock Island County, Illinois
Where the Rock River meets the Mississippi, Rock Island County anchors the Illinois side of the Quad Cities - a metro that straddles two states and has built its identity around river commerce, military manufacturing, and a shared regional economy that doesn't much care about state lines.
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Office: Rock Island County Sheriff’s Office – 1317 Third Avenue, County Justice Center, Rock Island, IL 61201 | (309) 794-1230 (24-hour non-emergency) | Fax (309) 794-9979. Hours: Mon-Fri 8 AM-4:30 PM. Handles roughly 40,000 calls annually. Rock Island County Correctional Center (completed 1986) has an annual jail population over 10,000, with an integrated Annex/Criminal Justice Center completed 2001. Specialized units include Water Rescue, Canine, Bomb Squad, school resource officers at three area high schools, and Metro-Link mass transit policing partnership.
Notes: For an active emergency, call 911. The Sheriff’s Office traces to 1833, when Rock Island County was commissioned and Benjamin F. Pike became its first sheriff; since the current jail opened in 1986, only three inmates have ever escaped.
Roads & Utilities
ROADS & TRANSPORTATION
Roads: I-74/80 serve Rock Island, the county seat, part of the Quad Cities metro area (with Moline, Illinois and Davenport/Bettendorf, Iowa).
Notes: Rock Island County is home to Rock Island Arsenal, a major U.S. Army manufacturing installation on Arsenal Island in the Mississippi River.
Business & Permits
BUILDING & PERMITS
Office: Rock Island County Courthouse – Rock Island, IL.
Notes: Rock Island County holds genuine national military-historical significance through the Rock Island Arsenal Museum, which opened July 4, 1905 as “The Ordnance Museum” – it is the second-oldest museum in the entire U.S. Army, behind only the West Point Museum (1854). Its collection traces to an 1903 shipment of foreign ordnance materiel sent for preservation and public display. A notable local figure, Morris E. Muhleman, served as Rock Island County Sheriff (1951-1955) before going on to the Illinois State Senate and then serving as Mayor of Rock Island (1961-1965).
Veterans Services
VETERANS SERVICES
Office: Rock Island County Veterans Assistance Commission – confirm current contact via rockislandcountyil.gov.
Libraries
LIBRARIES
Rock Island Public Library (Rock Island) – confirm current address/phone via the county library system.
Parks & Recreation
PARKS & RECREATION
Key Assets: The Rock Island Arsenal Museum (second-oldest U.S. Army museum), Arsenal Island’s historic sites, and the Mississippi River Quad Cities corridor are the county’s premier heritage and cultural attractions.
Notes: The genuine, deep national military history preserved at the Rock Island Arsenal Museum is among the standout local facts covered in this project.
GIS & Maps
GIS & MAPS
Appraisal/Parcel Search: Rock Island County Assessment Office – confirm current contact via rockislandcountyil.gov.
Animal Services
ANIMAL SERVICES
Confirm current dedicated shelter contact via rockislandcountyil.gov; Rock Island County Sheriff’s Office for animal control arrangements.
Environmental & Waste
ENVIRONMENTAL / WASTE MANAGEMENT
Office: Rock Island County Environmental Health – confirm current contact via rockislandcountyil.gov.
NOTES: Rock Island County is the seventy-second county completed in Illinois’s Round 3 v2 redo, under the A+ sourced standard established for this project. The genuine, deep national military history preserved at the Rock Island Arsenal Museum is among the standout local 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 Rock Island County
Rock Island County is the Illinois half of the Quad Cities metropolitan area, sharing an economy and daily life with Davenport and Scott County, Iowa across the Mississippi River. The county’s most significant geographic and economic feature is Rock Island Arsenal – a massive federal military installation on Arsenal Island in the middle of the Mississippi River that has manufactured and repaired military equipment since 1862. The Arsenal is the largest government-owned weapons manufacturing arsenal in the United States and employs thousands of civilian and military workers whose economic impact extends throughout the Quad Cities region. The island also houses the Rock Island National Cemetery and the former Confederate Prison Camp, where more than 1,900 Confederate prisoners died during the Civil War.
The county’s communities – Rock Island, Milan, East Moline (shared with Henry County), and Coal Valley – are working-class river cities with manufacturing heritage tied to John Deere, International Harvester (now CNH Industrial), and the broader agricultural equipment manufacturing cluster that has made the Quad Cities one of the most significant farm equipment production addresses in the world. Augustana College in Rock Island is a selective liberal arts institution with a strong Norse heritage and consistent national rankings. The riverfront development in Rock Island and the shared arts and entertainment infrastructure of the Quad Cities – the Figge Art Museum, Adler Theatre, RiverCenter – reflect a bi-state metropolitan area that functions as a single cultural unit.
All Services
Browse every category and topic available for this county.
Illinois assesses property at 33.33% of fair market value; Rock Island County conducts triennial reassessments. Property owners may appeal to the Board of Review within 30 days of assessment publication. The Senior Citizens Homestead Exemption reduces assessed value by $8,000; the Senior Citizens Assessment Freeze applies to residents 65+ with household income at or below $65,000. Illinois has an estate tax on estates above $4 million; no Illinois inheritance tax.
Courts & Legal
Courts & Legal
SENIOR SERVICES
Western Illinois Area Agency on Aging
729 34th Avenue, Rock Island, IL 61201
Phone: (309) 793-6800
Senior transportation, Meals on Wheels, caregiver support, legal assistance, and long-term care options counseling for Rock Island County residents.
Senior Services
Western Illinois Area Agency on Aging
729 34th Avenue, Rock Island, IL 61201
Phone: (309) 793-6800
Senior transportation, Meals on Wheels, caregiver support, legal assistance, and long-term care options counseling for Rock Island County residents.
Marriage & Vital Records
Marriage licenses, divorce records, and birth & death certificates are handled by the following office(s):
COUNTY CLERK (Records, Vital Records, Elections)
1504 3rd Ave., Rock Island, IL 61201
(309) 786-4451
CIRCUIT CLERK (Court Records, Marriage Licenses)
210 15th St., Rock Island, IL 61201
(309) 786-4451
ELECTIONS (County Clerk)
1504 3rd Ave., Rock Island, IL 61201
(309) 786-4451
Genealogy
County-level record sources
Rock Island County Circuit Clerk (probate/estate case files – see Probate section above).
The Rock Island Arsenal Museum documents the county’s significant military-industrial history dating to the Civil War era.
Local societies
No dedicated Rock Island 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
Rock Island County Circuit Clerk 1317 3rd Avenue, Suite 101, Rock Island, IL 61201 (309) 558-3538
Rock Island County is part of the Quad Cities region on the Mississippi River, home to the Rock Island Arsenal, one of the largest government-owned weapons manufacturing arsenals in the world.
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 Rock Island 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 Rock Island 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
1317 3rd Ave., Rock Island, IL 61201
(309) 794-6500
Elections & Voting
Voter registration, polling locations, and elections information are handled by the following office(s):
COUNTY CLERK (Records, Vital Records, Elections)
1504 3rd Ave., Rock Island, IL 61201
(309) 786-4451
ELECTIONS (County Clerk)
1504 3rd Ave., Rock Island, IL 61201
(309) 786-4451
Health & Human Services
Offices & Contacts
Health services, social services, and assistance programs are handled by the following office(s):
Rock Island County Health Dept
(309) 793-1955
IL DCFS — Rock Island
(309) 793-4900
IL Medicaid
(800) 843-6154
UnityPoint Health — Trinity (Moline)
unitypoint.org/trinity (major regional hospital; Level I Trauma)
Genesis Medical Center (Davenport/Silvis)
genesishealth.com
OSF Saint Anthony Rock Island
osfhealthcare.org/saint-anthony
Public Health Information
PUBLIC HEALTH
Office: Rock Island County Health Department – confirm current contact via rockislandcountyil.gov.
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Editorial Trust
5 official sources cited
Reviewed by CountyOffices Editorial Team
Last verified June 2026
County Facts
County Seat: Rock Island
Population: 143,000
Area: 427 sq mi
Established: 1831
Tier: 3
Inmate Services
Care Packages
Send care packages to inmates in Rock Island County facilities via Amazon.
