ZIP Codes of Marshall County, IL

Population & People
Population & People
Total Population
12,402
Household Income
Household Income
Median Income
$68,071
Housing
Housing
Total Housing Units
6,171
Business & Economy
Business & Economy
Total Businesses
258
Employment
Employment
Employment Rate
54.25%
Education
Education
Bachelor's Degree+
17.81%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 9 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:9 ZIP Codes (7 Standard, 2 PO Box, 0 Unique) [See All]
Area Codes:309 / 779 / 815 / 861
Timezone:Central (GMT -06:00)
Local Time:2:12:02 PM
Population:12,402 [See All]
FIPS:17123
CBSA:Peoria, IL
Land Area:392 sq mi
Water Area:16 sq mi
Coordinates:41.0233, -89.3322
Quick Link:
https://www.zip-codes.com/county/il-marshall.asp
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Illinois's #83 most populous county
12,402 residents across 9 ZIPs — #83 of 102 Illinois counties.

Standout ZIPs in this County


Most Populous
Lacon · 2,753 people
22.2% of county total
Highest Income
Varna · $81,293 median
1.2× county average
Largest Land Area
Washburn · 69.3 sq mi
Spans the most ground
Fastest Growth
Toluca · 2.5% (10-yr)
1,555 → 1,594 residents
Most Educated
Henry · 21.0% bachelor's+
413 of 1,964 adults 25+

Things worth knowing about Marshall County


12,402 residents live across 9 ZIPs covering 392 sq mi, served by 9 distinct USPS-recognized cities.

Population moved from 13,498 to 12,402 from 2014 to 2024 — a -8.1% change. 2 ZIPs gained residents, 7 lost.

The county's wealthiest ZIP 61375 (Varna, $81,293 median) and poorest ZIP 61541 (La Rose, $41,875) are 3.1 miles apart — a 1.9× income gap across local geography.

Median home values vary 2.3× across this county — from $72,900 in 61541 (La Rose) to $164,900 in 61375 (Varna).

Density varies 27× across the county — from 19 people/sq mi in 61565 (Sparland) to 518 in 61541 (La Rose).

Educational attainment ranges from 2.6% bachelor's+ in 61541 (La Rose) to 24.0% in 61565 (Sparland) — the breadth of educational profiles across the area.

Within Illinois, this is the #83 most populous of 102 counties and ranks #66 for median household income .

Weighted by population, the typical household earns about $71,389 across the county — reflecting what a typical resident sees, not a simple ZIP average.

17.8% of adults age 25+ hold a bachelor's degree or higher (1,617 of 9,078 reporting).

7 Standard delivery, 2 PO Box only, 0 single-entity Unique ZIPs serve this county.

Stories about Marshall County


Population decline

Marshall County lost 8.1% of residents between 2014 and 2024. ZIPs that shed the largest share:

Sparland
-23.8%
1,656 → 1,262 residents
Washburn
-15.2%
1,772 → 1,503 residents
Wenona
-14.3%
1,681 → 1,441 residents
Varna
-12.9%
1,135 → 989 residents

All ZIP Codes in Marshall County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
61540LaconStandard2,753$78,82457.72.5%
61537HenryStandard2,743$67,40457.6-1.4%
61369TolucaStandard1,594$68,70843.82.5%
61570WashburnStandard1,503$71,56369.3-15.2%
61377WenonaStandard1,441$57,32152.6-14.3%
61565SparlandStandard1,262$77,57865.1-23.8%
61375VarnaStandard989$81,29345.5-12.9%
61541La RosePO Box97$41,8750.2-24.8%
61424Camp GrovePO Box200.0-80.2%

Adjacent & Nearby Counties