LaSalle County, Illinois

LaSalle County population, land area and income

LaSalle County had 108,390 residents in the Census Vintage 2024 estimate, on 1,135.1 square miles of land. It ranks 17th of 102 in Illinois by population and 2nd by land area. That works out to 95.5 people per square mile, near the US average of 96.3, and above the national county median.

The median county-equivalent in Illinois has 24,447 residents, so LaSalle County is 4.4 times that size.

Its SAIPE 2023 median household income of $72,225 is above the national county median among 3,143 counties with an estimate.

How LaSalle County's population changed since 2020

LaSalle County lost 1,019 residents between the July 2020 and July 2024 estimates, a drop of 0.9%. That ranks 29th of 102 in Illinois for growth. The median Illinois county changed by -1.7%, and the state as a whole by -0.7%.

Since the April 2020 estimates base, LaSalle County recorded 4,721 births and 5,962 deaths, a natural change of -1,241. Net international migration added +520 and net domestic migration, people moving to or from other US counties, came to -601. The largest single component was natural change, which removed 1,241 people.

Where LaSalle County is

The Census internal point of LaSalle County is at 41.343300, -88.885900. It sits in UTM zone 16N. The map shades Illinois's 102 county-equivalents by population change from 2020 to 2024, darker for faster growth, with LaSalle County outlined. Dots are towns of 1,000+ people with residents in it.

Towns in LaSalle County

12 incorporated places of 1,000+ people have residents in LaSalle County, 73,421 people together, or 68% of the county. Each figure counts only the part of the town inside LaSalle County; towns marked "part" extend into another county. The largest is Ottawa with 18,775.

Counties bordering LaSalle County

The Census 2024 county adjacency file lists 9 neighbors for LaSalle County. The most populous is Kendall County, IL, with 143,171 residents. Distances run between Census internal points in a straight line.

• Kendall County

  143,171 people

  29 mi NE

• DeKalb County

  101,335 people

  39 mi N

• Grundy County

  53,835 people

  25 mi E

• Woodford County

  38,290 people

  42 mi SSW

• Livingston County

  35,375 people

  36 mi SSE

• Lee County

  33,544 people

  35 mi NW

• Bureau County

  32,486 people

  34 mi W

• Marshall County

  11,552 people

  32 mi SW

• Putnam County

  5,633 people

  24 mi WSW

Distance to Springfield and the nearest big city

Springfield is 115.2 miles SSW of LaSalle County's internal point in a straight line. The nearest place of 100,000 or more is Joliet, IL (population 151,837), 40.1 miles away. The nearest place of 10,000 or more is Ottawa, IL (population 18,775), 3.4 miles away.

LaSalle County FIPS code

The FIPS code of LaSalle County is 17099: state code 17 for Illinois plus county code 099. Use it as text, with the leading zero, when joining Census, BLS, or CDC county tables. SAIPE lists its 2023 median household income as $72,225.