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Illinois County
Jefferson County, Illinois
Mount Vernon's crossroads position and Illinois's southern gateway - from Mount Vernon's strategic position at the intersection of I-57 and I-64 (the convergence of two of Illinois's most important interstate highways makes Mount Vernon the primary crossroads community in southern Illinois - travelers between Chicago and Memphis and between St. Louis and the Indiana border pass through Mount Vernon) to the Illinois Supreme Court's historical Mount Vernon connection and Rend Lake's northern recreation access.
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Office: Jefferson County Sheriff’s Office – Jefferson County Justice Center, 911 Casey Avenue, Mount Vernon, IL 62864 | (618) 244-8004 / (618) 244-8002; Sheriff Roy Torgerson. Jail capacity 249 beds. High Risk Team (HRT), a joint unit with Mount Vernon Police created in 1995, currently 15 officers, some also serving on the regional ILEAS Weapons of Mass Destruction Special Response Team.
Notes: For an active emergency, call 911.
Roads & Utilities
ROADS & TRANSPORTATION
Roads: I-57/64 serve Mount Vernon, the county seat, principal city of the Mount Vernon Micropolitan Area (encompassing all of Jefferson and Hamilton counties).
Notes: Jefferson County was founded in 1819, named for Thomas Jefferson. The area’s first settlers, Andrew Moore and his family, arrived in 1810; Moore and one of his sons were killed in conflict with Native Americans, and his widow and remaining children relocated to Equality, Illinois. Mount Vernon itself was founded in 1817 by Zadok Casey, later a state senator, Illinois lieutenant governor (1833), and U.S. Congressman (1833-1843); commissioners chose the town’s name out of reverence for George Washington.
Business & Permits
BUILDING & PERMITS
Office: Jefferson County Courthouse – Mount Vernon, IL (built 1939 by the federal Works Progress Administration, the fifth courthouse to serve the county). The county’s very first courthouse, ordered at the commissioners’ first meeting, was a simple 18-by-20-foot log building with a single door and window, completed by September 1819 – though it proved impossible to keep warm through the winter and required prompt modification.
Notes: Mount Vernon holds genuine judicial significance beyond the county level: the 5th District Appellate Court building (Greek Revival, construction begun 1854; National Register of Historic Places since 1973) was originally built for the southern division of the Illinois Supreme Court, established under the 1848 Illinois Constitution.
Veterans Services
VETERANS SERVICES
Office: Jefferson County Veterans Assistance – confirm current contact via jeffersoncountyillinois.com.
Libraries
LIBRARIES
Mount Vernon Public Library (Mount Vernon) – confirm current address/phone via the county library system.
Parks & Recreation
PARKS & RECREATION
Key Assets: The historic 5th District Appellate Court building (National Register of Historic Places), the Jefferson County Courthouse, and downtown Mount Vernon – nicknamed “The King City” and “The Festival City” – are the county’s premier heritage attractions.
Notes: The genuine judicial history connecting Mount Vernon to the historic southern division of the Illinois Supreme Court is among the standout local facts covered in this project.
GIS & Maps
GIS & MAPS
Appraisal/Parcel Search: Jefferson County Assessor’s Office – confirm current contact via jeffersoncountyillinois.com.
Animal Services
ANIMAL SERVICES
Confirm current dedicated shelter contact via jeffersoncountyillinois.com; Jefferson County Sheriff’s Office for animal control arrangements.
Environmental & Waste
ENVIRONMENTAL / WASTE MANAGEMENT
Office: Jefferson County Environmental Health – confirm current contact via jeffersoncountyillinois.com.
NOTES: Jefferson County is the forty-first county completed in Illinois’s Round 3 v2 redo, under the A+ sourced standard established for this project. The genuine judicial history connecting Mount Vernon to the historic southern division of the Illinois Supreme Court 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 Jefferson County
Jefferson County is southern Illinois’s interstate crossroads county – a community whose geographic position at the junction of I-57 and I-64 makes it the functional hub of the region’s transportation network.
Mount Vernon (the county seat, population ~15,000) has built a service economy around its highway crossroads position – hotels, restaurants, truck stops, and retail serve the enormous volume of interstate traffic passing through. The city’s hospital and retail draw from a broad southern Illinois region.
Rend Lake – straddling the Franklin-Jefferson county line – provides the county’s primary recreation asset, with boating, fishing, golf, and camping on a 19,000-acre reservoir.
All Services
Browse every category and topic available for this county.
Jefferson County Assessor at 100 S. 10th Street, Mount Vernon, IL 62864, phone 618-244-8020. IL residential assessed at 33.33% of market value. Appeal to Board of Review.
Courts & Legal
Jefferson County Circuit Court at 100 S. 10th Street, Mount Vernon, IL 62864, phone 618-244-8007, 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)
100 S. 10th St., Mount Vernon, IL 62864
(618) 244-8007
CIRCUIT CLERK (Court Records, Marriage Licenses)
100 S. 10th St., Mount Vernon, IL 62864
(618) 244-8060
ELECTIONS (County Clerk)
100 S. 10th St., Mount Vernon, IL 62864
(618) 244-8007
Genealogy
County-level record sources
Jefferson County Circuit Clerk (probate/estate case files – see Probate section above).
Local societies
No dedicated Jefferson 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
Jefferson County Circuit Clerk (Second Judicial Circuit) 100 South 10th Street, Mt. Vernon, IL 62864 (618) 244-8007
Jefferson County’s seat, Mount Vernon, sits at the crossroads of I-57 and I-64 in southern Illinois and is home to the Illinois Fifth District Appellate Court.
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 Jefferson 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. Note: the Circuit Clerk maintains files for Traffic, Criminal, Divorce, Small Claims, Law, Probate, Adoption, Family, Juvenile, Orders of Protection, Chancery, Miscellaneous Remedy, DUI, and Tax cases.
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 Jefferson 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
400 W. Potomac Blvd., Mount Vernon, IL 62864
(618) 244-8004
Elections & Voting
Voter registration, polling locations, and elections information are handled by the following office(s):
COUNTY CLERK (Records, Vital Records, Elections)
100 S. 10th St., Mount Vernon, IL 62864
(618) 244-8007
ELECTIONS (County Clerk)
100 S. 10th St., Mount Vernon, IL 62864
(618) 244-8007
Health & Human Services
Offices & Contacts
Health services, social services, and assistance programs are handled by the following office(s):
Jefferson County Health Dept
(618) 244-7399
IL DCFS — Mount Vernon
(618) 244-8010
IL Medicaid
(800) 843-6154
CrossRoads Community Hospital
crossroadscommunityhospital.com (Mount Vernon)
Heartland Regional Medical Center
heartlandregional.com (Marion)
Public Health Information
PUBLIC HEALTH
Office: Jefferson County Health Department – confirm current contact via jeffersoncountyillinois.com.
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Last verified June 2026
County Facts
County Seat: Mount Vernon
Population: 38,000
Area: 571 sq mi
Established: 1819
Tier: 3
Public Records
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Search public records for Jefferson County residents.
