Population109,658 (2020 Census)
River Valleys Reveal Towns with Deep Roots
LaSalle County, IllinoisOttawa lies where the Fox and Illinois rivers meet. The county’s river valleys connect its communities with landscapes associated with Starved Rock and the Illinois and Michigan Canal. This guide brings together a starting point for county information, public services and local connections. Begin with Ottawa, 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.
LaSalle County at a Glance
Population109,658 (2020 Census)
County SeatOttawa
Largest MunicipalityOttawa
Established1831
ZIP Codes28 ZIP codes wholly or partly within the county (checked October 4, 2026)
Total Area1,148.2 sq mi (land and water; 2020 Census geography)
Major RoutesInterstates 39 and 80; U.S. Routes 6, 34 and 52; Illinois Routes 17, 18, 23, 71, 170, 178, 179, 251 and 351
Area Codes779 / 815 (common local area codes)
Meet Your County Advertisers
Local Connections for Everyday Needs
Explore Prairie State Water Systems Inc for water well systems.
Discover LaSalle County
LaSalle County
The county was established in 1831 and named for the explorer La Salle. Rivers, canal transport and later railroads shaped connections among its towns. Today, Ottawa remains the county seat, while Ottawa is its largest municipality. The 2020 Census counted 109,658 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 LaSalle County extends beyond a single town center. River valleys and canal history 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 1831, LaSalle 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
River valleys and canal history help distinguish LaSalle County. Its county seat, Ottawa, 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 LaSalle County.
Explore the towns, follow the stories, make local connections.
A Look Around
Scenes from LaSalle County
Places and details that tell a local story.
Shaw Local
LaSalle County Retired Teachers to hold general meeting Sept. 28 in Oglesby
Read the full story at Shaw Local.
Read the Story Sep 25, 2026 • Local news
Around LaSalle County
Stories from every corner of LaSalle County.
Keep These Businesses in Mind
Start with a Direct Conversation
Contact Prairie State Water Systems Inc 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 (815) 434-8233
Schools
County & Local Resources
Hospitals and Health
County & Local Resources
Morris Hospital & Healthcare Centers
Regional option in Grundy County
Address 150 W HIGH ST, Morris
Phone (815) 942-2932
Osf Saint Clare Medical Center
Regional option in Bureau County
Address 530 PARK AVENUE EAST, Princeton
Phone (815) 875-2811
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
Gebhard Woods State Park
Morris — regional option in Grundy County. Check facilities and access notices.
Mazonia-Braidwood State Fish & Wildlife Area
Braceville — regional option in Grundy County. Check facilities and access notices.
Marshall State Fish and Wildlife Area
Lacon — regional option in Marshall County. Check facilities and access notices.
Trails
County & Local Resources
Adventur-E-Bike Rental LLC
Utica, LaSalle County. Check trail access and permitted uses.
Illinois & Michigan Canal State Trail
LaSalle, LaSalle 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
Earlville Public Library District
Address 205 Winthrop Street Post Office Box 420 Earlville , IL 60518-0420
Phone 815-246-9543
Graves-Hume Public Library District
Address 1401 West Main Street Mendota , IL 61342-2500
Phone 815-538-5142
Lostant Community Library
Address 102 West Third Street Post Office Box 189 Lostant , IL 61334-0189
Phone 815-368-3530
Marseilles Public Library
Address 155 East Bluff Street Marseilles , IL 61341-1442
Phone 815-795-4437
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 LaSalle County
Find background and service information below, then follow the provider links for current details.
Ottawa is the county seat. LaSalle County Government provides county office information; check the office destination before traveling.
Ottawa is the largest municipality listed in the county reference. Countywide statistics include other communities and unincorporated areas as well.
The 2020 Census counted 109,658 residents. This is a decennial count, not a current-year population estimate.
LaSalle County was established in 1831. The county was established in 1831 and named for the explorer La Salle. Rivers, canal transport and later railroads shaped connections among its towns.
The county covers approximately 1,148.2 sq mi (land and water; 2020 Census geography). This total includes both land and water, rather than land area alone.
Ottawa lies where the Fox and Illinois rivers meet. The county’s river valleys connect its communities with landscapes associated with Starved Rock and the Illinois and Michigan Canal.
Woody's Orchard is in Plano, Kendall County. This is a regional option outside LaSalle 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.
Buffalo Rock State Park is in Ottawa, LaSalle County. Check the provider’s current opening times and visitor information before traveling.
Buffalo Rock State Park is in Ottawa, LaSalle 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 Prairie State Water Systems Inc for water well systems.
My Local Guide
Find Something Fun
Explore Local PlacesPlan your next stop around current information from each place.
Kids’ Fun
- Woody's Orchard — Plano — regional option in Kendall County
- Raging Waves Waterpark — Yorkville — regional option in Kendall County
- Sugar Grove Family Fun Center — Sugar Grove — regional option in Kane County
Restaurants
- The Cheese Shop 'n' Deli — Ottawa, LaSalle County
- Woody's Steakhouse — Ottawa, LaSalle County
- Hi-Way Restaurant — Ottawa, LaSalle County
Shopping & Retail
- Starved Rock Hot Glass — Ottawa, LaSalle County
- Heartland by Hand — Ottawa, LaSalle County
- Lady Di's — Ottawa, LaSalle County
Clothing & Boutiques
- Heartland by Hand — Ottawa, LaSalle County
- Lady Di's — Ottawa, LaSalle County
- Starved Rock Lodge Gift Shop — Oglesby, LaSalle County
Outdoor Fun
- Buffalo Rock State Park — Ottawa, LaSalle County
- Awesome Ottawa Tours — Ottawa, LaSalle County
- Catlin Park — Ottawa, LaSalle County
Free Things To Do
- Buffalo Rock State Park — Ottawa, LaSalle County; basic grounds/trail visit. Rentals, camping, special activities or events may cost extra.
- Matthiessen State Park — Utica, LaSalle County; basic grounds/trail visit. Rentals, camping, special activities or events may cost extra.
- Donnelley/Depue State Fish and Wildlife Area & Complex — De Pue — regional option in Bureau County; basic grounds/trail visit. Rentals, camping, special activities or events may cost extra.
Make Time for Local DiscoveriesChoose Your Next Stop