Population37,113 (2020 Census)
Southern Crossroads Center on a Historic City
Jefferson County, IllinoisMount Vernon is the county seat and largest city. Interstates 57 and 64 connect its services and businesses with the surrounding communities of southern Illinois. This guide brings together a starting point for county information, public services and local connections. Begin with Mount Vernon, then use the resource links to plan the details of a visit or an everyday errand. Check directly with each provider for current hours, access and service availability before setting out.
Jefferson County at a Glance
Population37,113 (2020 Census)
County SeatMount Vernon
Largest MunicipalityMount Vernon
Established1819
ZIP Codes15 ZIP codes wholly or partly within the county (checked October 4, 2026)
Total Area583.8 sq mi (land and water; 2020 Census geography)
Major RoutesInterstate 57; Interstate 64; U.S. Highway 51; Illinois Route 15; Illinois Route 37
Area Codes618 / 730 (common local area codes)
Meet Your County Advertisers
Local Connections for Everyday Needs
Explore Archway RV Park, Black Tie Affair LLC, Linus Rapp Construction, McDermott Sales & Service for RV stays, formalwear, construction and remodeling, towing and roadside service.
Discover Jefferson County
Jefferson County
The county was established in 1819 and named for Thomas Jefferson. Mount Vernon became the center of county government within the region often called Little Egypt. Today, Mount Vernon remains the county seat, while Mount Vernon is its largest municipality. The 2020 Census counted 37,113 residents across the county. Its towns and surrounding countryside offer different ways to understand the same place: through public buildings, transportation routes and the communities that connect them. Local records and historical collections provide a starting point for exploring how those connections changed over time.
Life in Jefferson County extends beyond a single town center. Mount Vernon and regional travel are part of the local setting, alongside the routine needs of households, schools and businesses. Use county offices for the services they administer and contact municipal or township offices when a question concerns a specific address. Planning around the actual destination helps make visits, appointments and local errands more practical, especially when travel crosses town or county boundaries.
What Shapes Us
Local Heritage
Established in 1819, Jefferson County has a history recorded in its communities and public institutions. Start with local collections to explore specific people, buildings and events.
Landscape and Connections
Mount Vernon and regional travel help distinguish Jefferson County. Its county seat, Mount Vernon, provides a useful starting point for understanding how nearby communities connect across the area.
Everyday Community
County and local offices connect residents with practical services. Follow the linked providers for details specific to your destination, address and purpose in Jefferson County.
Explore the towns, follow the stories, make local connections.
A Look Around
Scenes from Jefferson County
Places and details that tell a local story.
WMIX
Overnight closures planned on I-57 and I-64 in Jefferson County Oct. 22-23
Read the full story at WMIX.
Read the Story Oct 19, 2026 • Local news
Around Jefferson County
Stories from every corner of Jefferson County.
Overnight closures planned on I-57 and I-64 in Jefferson County Oct. 22-23
Read the full story at WMIX.
Oct 19, 2026 • Local news
Jefferson County Fire District Visits the RLCF Children’s Center
Read the full story at WMIX.
Oct 19, 2026 • Local news
De Soto man charged with murder after woman fatally shot in Jefferson County
Read the full story at KBSI Fox 23 Cape Girardeau News | Paducah News.
Oct 12, 2026 • Local news
Jefferson County Heritage Festival Saturday October 3rd
Read the full story at WMIX.
Oct 1, 2026 • Local news
Salem Economic Development Director Resigns; Going to Jefferson County
Read the full story at WJBD.
Oct 1, 2026 • Local news
Keep These Businesses in Mind
Start with a Direct Conversation
Contact Archway RV Park, Black Tie Affair LLC, Linus Rapp Construction, McDermott Sales & Service directly to ask about current options, availability and the services you need.
County Resources
Find the Right Local Connection
Start with the responsible public agency or service provider. Statewide links are labeled so you can locate the office that serves your address.
Government
County & Local Resources
Supervisor of Assessments
Property assessments, exemptions and assessment office information.
Phone (618) 244-8016
Schools
County & Local Resources
Farrington CCSD 99 — official district profile
Address 20941 E Divide Rd, Bluford
Phone 618-755-4414
Hospitals and Health
County & Local Resources
Franklin Hospital
Regional option in Franklin County
Address 201 BAILEY LANE, Benton
Phone (618) 439-3161
Salem Township Hospital
Regional option in Marion County
Address 1201 RICKER DRIVE, Salem
Phone (618) 548-3194
Ssm Health St Mary'S Hospital -Centralia
Regional option in Marion County
Address 400 NORTH PLEASANT AVENUE, Centralia
Phone (618) 436-8000
Public Safety
County & Local Resources
Illinois State Police
Statewide or federal resource; select the office or service for your address.
Illinois State Police contacts
Find the appropriate State Police contact; call 911 for emergencies.
FBI Internet Crime Complaint Center
Report cyber-enabled crime through the federal complaint portal; emergencies require 911.
Emergency Services
County & Local Resources
Illinois Emergency Management Agency and Office of Homeland Security
Statewide or federal resource; select the office or service for your address.
National Weather Service
Statewide or federal resource; select the office or service for your address.
State Parks
County & Local Resources
Wayne Fitzgerrell State Park
Whittington — regional option in Franklin County. Check facilities and access notices.
Hamilton County State Fish And Wildlife Area
McLeansboro — regional option in Hamilton County. Check facilities and access notices.
Ten Mile Creek State Fish and Wildlife Area
McLeansboro — regional option in Hamilton County. Check facilities and access notices.
Sam Dale Lake Conservation Area
Johnsonville — regional option in Wayne County. Check facilities and access notices.
Sahara Woods
Carrier Mills — regional option in Saline County. Check facilities and access notices.
Trails
County & Local Resources
Rend Lake Bike Trail
Benton — regional option in Franklin County. Check trail access and permitted uses.
Stephen A. Forbes State Park
Kinmundy — regional option in Marion County. Check trail access and permitted uses.
Washington County State Recreation Center
Nashville — regional option in Washington County. Check trail access and permitted uses.
Eldon Hazlet State Park
Carlyle — regional option in Clinton County. Check trail access and permitted uses.
Boulder Recreation Area Camping
Carlyle — regional option in Clinton County. Check trail access and permitted uses.
Utilities
County & Local Resources
Illinois Commerce Commission
Statewide or federal resource; select the office or service for your address.
Illinois 811 — JULIE
Statewide or federal resource; select the office or service for your address.
Illinois energy assistance
Find utility-bill assistance and the local administering agency.
Libraries
County & Local Resources
C.E. Brehm Memorial Public Library District
Address 101 South Seventh Street Mount Vernon , IL 62864-4114
Phone 618-242-6322
Ashley Public Library District
Regional library in Washington County; check borrowing eligibility
Address 70 North Second Street Ashley , IL 62808-0246
Phone 618-485-2295
Nashville Public Library
Regional library in Washington County; check borrowing eligibility
Address 219 East Elm Street Nashville , IL 62263-1711
Phone 618-327-3827
Evans Public Library District
Regional library in Fayette County; check borrowing eligibility
Address 825 West Randolph Street Vandalia , IL 62471-2703
Phone 618-283-2824
Ramsey Public Library
Regional library in Fayette County; check borrowing eligibility
Address 401 South Superior Street Ramsey , IL 62080-0128
Phone 618-423-2019
Courts
County & Local Resources
Illinois Courts
Statewide or federal resource; select the office or service for your address.
Illinois Courts — Forms
Statewide or federal resource; select the office or service for your address.
Illinois Court Help
Court-process information and help for people without an attorney.
DMV
County & Local Resources
Transportation
County & Local Resources
Illinois Department of Transportation
Statewide or federal resource; select the office or service for your address.
Getting Around Illinois
Statewide or federal resource; select the office or service for your address.
Illinois public transportation
Find public transportation information and regional agencies.
IDOT transit programs
Transit program information, including rural and intercity services.
Amtrak Illinois services
Find Illinois intercity rail routes and stations; some counties require travel to a regional station.
Postal Services
County & Local Resources
USPS Location Finder
Statewide or federal resource; select the office or service for your address.
USPS ZIP Code Lookup
Statewide or federal resource; select the office or service for your address.
USPS Informed Delivery
Statewide or federal resource; select the office or service for your address.
Veterans
County & Local Resources
Illinois Department of Veterans Affairs
Statewide or federal resource; select the office or service for your address.
VA Facility Locator
Statewide or federal resource; select the office or service for your address.
Veterans Crisis Line
Statewide or federal resource; select the office or service for your address.
Employment
County & Local Resources
IllinoisJobLink — official job-seeker help
Statewide or federal resource; select the office or service for your address.
Illinois Department of Employment Security
Statewide or federal resource; select the office or service for your address.
Illinois workNet
Statewide or federal resource; select the office or service for your address.
Work for Illinois
Statewide or federal resource; select the office or service for your address.
A Useful Starting Point
County facts and practical links for everyday questions.
Questions and Answers
Get to Know Jefferson County
Find background and service information below, then follow the provider links for current details.
Mount Vernon is the county seat. Jefferson County Government provides county office information; check the office destination before traveling.
Mount Vernon is the largest municipality listed in the county reference. Countywide statistics include other communities and unincorporated areas as well.
The 2020 Census counted 37,113 residents. This is a decennial count, not a current-year population estimate.
Jefferson County was established in 1819. The county was established in 1819 and named for Thomas Jefferson. Mount Vernon became the center of county government within the region often called Little Egypt.
The county covers approximately 583.8 sq mi (land and water; 2020 Census geography). This total includes both land and water, rather than land area alone.
Mount Vernon is the county seat and largest city. Interstates 57 and 64 connect its services and businesses with the surrounding communities of southern Illinois.
Breezy Hill Farm is in Benton, Franklin County. This is a regional option outside Jefferson County. Check the provider’s current opening times and visitor information before traveling.
Use USPS ZIP Code Lookup with the full street address. A county boundary does not define a single postal delivery area.
Mt. Vernon Veterans Park is in Mount Vernon, Jefferson County. Check the provider’s current opening times and visitor information before traveling.
Wayne Fitzgerrell State Park is in Whittington, Franklin County. This is a regional option outside Jefferson County. Basic access is the free activity; extras may carry charges. Check the provider’s current opening times and visitor information before traveling.
Begin with the Illinois Department of Veterans Affairs to locate the appropriate service office, or the VA facility locator for federal facilities.
Meet Your County Advertisers
Local Connections for Everyday Needs
Explore Archway RV Park, Black Tie Affair LLC, Linus Rapp Construction, McDermott Sales & Service for RV stays, formalwear, construction and remodeling, towing and roadside service.
My Local Guide
Find Something Fun
Explore Local PlacesPlan your next stop around current information from each place.
Kids’ Fun
- Breezy Hill Farm — Benton — regional option in Franklin County
- Rainbow Ranch Petting Zoo — Nashville — regional option in Washington County
- Little Grassy Fish Hatchery — Makanda — regional option in Williamson County
Restaurants
- Farmhouse Bakery & Cafe — Mount Vernon, Jefferson County
- Moe's Southwest Grill — Mount Vernon, Jefferson County
- Joe's Pizza — Mount Vernon, Jefferson County
Shopping & Retail
- Little Britches Boutique — Mount Vernon, Jefferson County
- Uncle Joe's Deli — Ina, Jefferson County
- Wayward Wovens — Du Quoin — regional option in Perry County
Clothing & Boutiques
- Laced 'N Grace — Mount Vernon, Jefferson County
- Little Britches Boutique — Mount Vernon, Jefferson County
- 5 T's Custom Creations — Herrin — regional option in Williamson County
Outdoor Fun
- Mt. Vernon Veterans Park — Mount Vernon, Jefferson County
- Wayne Fitzgerrell State Park — Whittington — regional option in Franklin County
- Rend Lake Bike Trail — Benton — regional option in Franklin County
Free Things To Do
- Wayne Fitzgerrell State Park — Whittington — regional option in Franklin County; basic grounds/trail visit. Rentals, camping, special activities or events may cost extra.
- Ten Mile Creek State Fish and Wildlife Area — McLeansboro — regional option in Hamilton County; basic grounds/trail visit. Rentals, camping, special activities or events may cost extra.
- Sam Dale Lake Conservation Area — Johnsonville — regional option in Wayne County; basic grounds/trail visit. Rentals, camping, special activities or events may cost extra.
Make Time for Local DiscoveriesChoose Your Next Stop