What is the largest city in Knox County, IL?

Galesburg is the largest city or town in Knox County, with about 29,481 residents.

How many ZIP codes are in Knox County?

Knox County includes 17 ZIP Code Tabulation Areas, including 61401, 61402, 61410, 61414, 61428.

What is the population of Knox County, IL?

About 49,046 people live in Knox County, based on American Community Survey 5-year estimates.

What counties border Knox County?

Knox County borders Peoria County, Henry County, Fulton County, Warren County, Mercer County, Stark County.

Knox County, IL: Cities, ZIP Codes & Local Data

Population

49,046

Land area

716sq mi

People per sq mi

68

ZIP codes

17

Knox County at a glance

Knox County is 70% less dense than Illinois as a whole.
The median household income is $57,030, 32% below the Illinois median of $83,390.
A typical owner-occupied home is valued at $111,900 (58% below Illinois) and median rent is $788 a month.
Its largest cities are Galesburg (29,481), Abingdon (3,443) and Knoxville (3,211).

Local data for Knox County, IL

Counts from official public data

Housing and community stats

Knox County, IL, American Community Survey 2020-2024

Full profile

Median household income

$57,030

Poverty rate

14.6%

Median home value

$111,900

Prices +5.5% in a year

Median rent

$788/mo

Homeownership

70.8%

Bachelor's or higher

21.0%

Median age

42.6

Average commute

20.4 min

Largest reported origins and ancestries: German Americans (8,580), Irish Americans (6,743), Swedish Americans (3,093).

Home values and rents Income, education and commute

Economy and federal money

Jobs, income, federal spending and pandemic loans

Details

Unemployment rate

4.3%

Sep 2026, -1.0 pts in a year

Average annual pay

$49,451

17,188 jobs, 2025

Income per person

$51,995

BEA, 2024

Federal spending

$351M

FY 2026, $7,027 per person

PPP loans

$86.9M

1,833 loans, 11,213 jobs reported

Campaign donations

$172K

Itemized, 2026 cycle

Economy Federal spending PPP loans

How people get to work

Knox County, IL, workers 16 and older. American Community Survey 5-year estimates

Drove alone79.1%
Carpooled8.9%
Public transit0.5%
Walked4.1%
Bicycle0.3%
Taxi, ride-hailing, motorcycle or other1.4%
Worked from home5.7%

Average one-way commute: 20.4 minutes for people who do not work from home.

Environment and hazard risk

Knox County, IL, from FEMA, NOAA and EPA

Full report

Natural hazard risk

Relatively Low

Top: strong wind

Storm events since 1996

476

Most often thunderstorm wind

Flood insurance policies

29

0.1% of homes, county

July high / Jan low

84° / 14°F

40.5 inches of rain a year

Hazards, floods and storm history Check a flood zone 6 historic places

Health statistics

Share of adults in Knox County, IL, CDC PLACES estimates

All 40 measures

Obesity

39.2%

U.S. 33.3% +5.9 pts

Diabetes

13.5%

U.S. 12.1% +1.4 pts

Smoking

16.0%

U.S. 12.8% +3.2 pts

Uninsured (18-64)

9.3%

U.S. 11.1% -1.8 pts

Cities, towns and ZIP codes in Knox County

Population shown

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Frequently asked questions

What is the largest city in Knox County, IL?: Galesburg is the largest city or town in Knox County, with about 29,481 residents.
How many ZIP codes are in Knox County?: Knox County includes 17 ZIP Code Tabulation Areas, including 61401, 61402, 61410, 61414, 61428.
What is the population of Knox County, IL?: About 49,046 people live in Knox County, based on American Community Survey 5-year estimates.
What counties border Knox County?: Knox County borders Peoria County, Henry County, Fulton County, Warren County, Mercer County, Stark County.