Illinois Counties
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Illinois Counties

There are one hundred and two counties in Illinois. St. Clair County was the first county established in what is today Illinois. Most counties in Illinois were named after early American leaders, especially of the American Revolutionary War, as well as soldiers from the Battle of Tippecanoe and the War of 1812.

LaSalle County, Illinois

LaSalle County Education, Geography, and HistoryLaSalle County, Illinois Courthouse

LaSalle County is located in the North Central region of the state of Illinois; according to the 2010 census, it had a population of 113,924. LaSalle County was created on January 15, 1831. The county seat and largest city is Ottawa. The county is named for Sieur de la Salle (1643-1687), French explorer of the Great Lakes.

LaSalle County is part of the Ottawa-Peru, IL Micropolitan Statistical Area, which is also included in the Chicago-Naperville, IL-IN-WI Combined Statistical Area.

Etymology - Origin of LaSalle County Name

LaSalle county was named after Robert de la Salle, a French explorer who sailed down the Mississippi River to the Gulf of Mexico and claimed the region for France.  De la Salle was responsible for the first European settlements in the area - Fort Crevecoeur on the Illinois River near Peoria in 1680, and Fort St. Louis on Starved Rock in 1682.


County QuickFacts: CensusBureau Quick Facts

LaSalle County History

LaSalle County was originally part of Putnam County, which had been established in 1825 Because of the lack of population, the original Putnam County was reorganized and at act on January 15, 1831 established three counties - Cook, Putnam and LaSalle County.  In 1831, LaSalle County covered parts of present-day Kendall, Livingston, and Marshall Counties, and the entirety of present-day Grundy County. The current boundaries of LaSalle County were established in 1843.

LaSalle County borders Woodford, Marshall, Putnam, Bureau, Livingston, Lee, DeKalb, Kendall, and Grundy counties. Though LaSalle County is in the Chicago media market, it retains a unique identity with a mix of pleasant river towns, and vast expanses of farmland. The county is at the intersection of the Chicago, Peoria, Quad Cities and Rockford television markets, with all four regions advertising (and businesses from the respective regions) and having a strong influence on the area such that despite the county's short distance from Chicago, approximately 60 miles (97 km). The county is part of the far southwestern reaches of the Chicago metropolitan area, and it is also part of the Fox Valley subregion and the larger Northern Illinois region.

Geography: Land and Water

As reported by the Census Bureau, the county has a total area of 1,148 square miles (2,973 km2), of which, 1,135 square miles (2,939 km2) of it is land and 13 square miles (34 km2) of it (1.14%) is water.

 LaSalle County is located in the North Central region of the Illinois.  Starved Rock State Park, LaSalle Lake State Fish & Wildlife Area, Illini State Park, Buffalo Rock State Park & Effigy Tumuli and Matthiessen State Park are located in this county.

Neighboring Counties

Bordering counties are as follows:

  • North: DeKalb County
  • Northeast: Kendall County
  • East: Grundy County
  • Southeast: Livingston County
  • Southwest: Woodford County; Marshall County; Putnam County
  • West: Bureau County
  • Northwest: Lee County


Secondary schools


  • Earlville High School (CUSD 9), also has district area in DeKalb and Lee Counties
  • LaSalle-Peru High School, LaSalle
  • Leland High School, Leland, also has district area in DeKalb County
  • Mendota Township High School, Mendota, also has district area in Bureau and Lee Counties
  • Newark Community High School, located within Kendall County, but serves Mission Township
  • Ottawa Township High School, Ottawa
  • Sandwich Community High School (CUSD 430), located within DeKalb County, but serves Northville Township
  • Seneca High School, also has district area in Grundy County
  • Serena High School (CUSD 2)
  • Somonauk High School, located within DeKalb County, but serves Northville and Adams Townships
  • Streator Township High School, Streator
  • Woodland High School, Streator


  • Marquette High School, Ottawa
  • St. Bede Academy, Peru

Colleges and universities

  • Illinois Valley Community College, Oglesby and Ottawa

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