• county
  • FIPS 17189
  • Largest town: Nashville

Washington County, Illinois

Washington County had 13,535 residents in the Census Vintage 2024 estimate, on 562.6 square miles of land. It ranks 76th of 102 in Illinois by population and 44th by land area.

Population
13,535
#76 of 102 in Illinois · #2,186 in US
Area
562.6 sq mi
#44 of 102 in Illinois · #1,836 in US
Density
24 / sq mi
#84 of 102 in Illinois · #2,090 in US
Median household income
$74,848
#21 of 102 in Illinois · #675 in US

Census Vintage 2024 estimates · SAIPE 2023 income · 2024 Gazetteer land area

Washington County within Illinois. Pin: Springfield.

Measure from here

Tools and pages that start from Washington County

Washington County population, land area and income

Washington County had 13,535 residents in the Census Vintage 2024 estimate, on 562.6 square miles of land. It ranks 76th of 102 in Illinois by population and 44th by land area. That works out to 24.1 people per square mile, below the US average of 96.3, and below the national county median.

The median county-equivalent in Illinois has 24,447 residents; Washington County is somewhat smaller.

Its SAIPE 2023 median household income of $74,848 is in the top quarter among 3,143 counties with an estimate.

National rank among 3,144

Population

13,535

3144th1st

2186th of 3,144 (US)

Land area

563 sq mi

3144th1st

1836th of 3,144 (US)

Density

24.1 / sq mi

3144th1st

2090th of 3,144 (US)

Median household income

$74,848

3143rd1st

675th of 3,143 (US)

Rank within Illinois (102)

Population

13,535

102nd1st

76th of 102 (IL)

Land area

563 sq mi

102nd1st

44th of 102 (IL)

Density

24.1 / sq mi

102nd1st

84th of 102 (IL)

Median household income

$74,848

102nd1st

21st of 102 (IL)

How Washington County's population changed since 2020

Washington County lost 196 residents between the July 2020 and July 2024 estimates, a drop of 1.4%. That ranks 42nd 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, Washington County recorded 559 births and 750 deaths, a natural change of -191. Net international migration added +2 and net domestic migration, people moving to or from other US counties, came to -33. The largest single component was natural change, which removed 191 people.

13.7k202013.7k202113.7k202213.6k202313.5k2024
Census Vintage 2024 county estimates for July 1 of each year. The axis starts above zero so year-to-year changes are visible.

Components of change, April 2020 to July 2024

Births
559
Deaths
750
Net international migration
+2
Net domestic migration
-33
Change, July 2023 to July 2024
-35

Where Washington County is

The Census internal point of Washington County is at 38.353100, -89.417200. 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 Washington County outlined. Dots are towns of 1,000+ people with residents in it.

Piatt County: -0.3%Hamilton County: -2.2%Williamson County: -0.1%Edgar County: -2.4%Macoupin County: -2.3%Marshall County: -1.3%Putnam County: +0.0%Richland County: -2.8%Washington County: -1.4%Lee County: -1.5%Douglas County: +0.2%Cook County: -1.6%Effingham County: -0.3%Edwards County: -3.6%Cass County: -2.0%Clay County: -3.4%Knox County: -2.2%LaSalle County: -0.9%Cumberland County: -1.3%Warren County: -3.7%Moultrie County: -0.9%Menard County: -2.5%Fayette County: -1.5%Boone County: -0.0%Lawrence County: -3.2%Marion County: -3.2%Champaign County: +3.0%Clark County: -2.4%Ford County: -0.4%Wayne County: -1.4%Logan County: -1.4%Grundy County: +2.5%Jasper County: -1.8%Crawford County: -1.3%McDonough County: -1.7%Clinton County: +0.5%Perry County: -3.0%Montgomery County: -2.2%Henry County: -2.0%Livingston County: -1.2%Scott County: -3.8%Alexander County: -11.2%Bureau County: -2.2%Brown County: +1.1%Mason County: -3.9%Calhoun County: -4.1%Greene County: -4.3%Coles County: -1.4%Kendall County: +8.2%Lake County: +0.7%Mercer County: -2.2%St. Clair County: -2.3%Wabash County: -3.0%Bond County: -1.7%DuPage County: +0.6%Gallatin County: -5.2%Stephenson County: -3.3%McHenry County: +1.9%White County: -3.0%Saline County: -3.9%Christian County: -2.2%Sangamon County: -1.0%Massac County: -3.6%Macon County: -2.9%Johnson County: -0.0%Jo Daviess County: -2.6%Peoria County: -1.0%DeKalb County: +1.0%Pope County: -1.5%De Witt County: -0.9%Schuyler County: -1.7%Fulton County: -3.1%Ogle County: -0.8%Jersey County: -1.6%Iroquois County: -3.3%Kankakee County: -0.9%Rock Island County: -1.1%Pulaski County: -5.8%Kane County: +0.9%Union County: -2.4%Whiteside County: -1.7%Woodford County: -0.3%Carroll County: -1.5%Adams County: -2.3%Hardin County: -2.6%Madison County: -1.0%Hancock County: -3.1%Monroe County: +0.0%Tazewell County: -1.1%Jackson County: -0.1%Vermilion County: -3.9%Randolph County: -0.6%McLean County: +0.5%Morgan County: -2.6%Shelby County: -1.7%Will County: +1.7%Winnebago County: -0.4%Jefferson County: -2.4%Stark County: -2.2%Henderson County: -4.5%Pike County: -2.6%Franklin County: -1.8%
Change 2020 to 2024
  1. < -3.0%
  2. < -2.2%
  3. < -1.4%
  4. < -0.3%
  5. ≥ -0.3%
no data

Orange pin: Washington County internal point. Dark pin: Springfield.

Internal point

Decimal
38.353100, -89.417200
DMS
38°21'11.16"N 89°25'1.92"W
UTM
16N 288783.4E 4247758.9N
Geohash
dnb6jmbrh
Plus code
86CG9H3M+64

Towns in Washington County

3 incorporated places of 1,000+ people have residents in Washington County, 4,361 people together, or 32% of the county. Each figure counts only the part of the town inside Washington County; towns marked "part" extend into another county. The largest is Nashville with 3,006.

  1. 01Nashville3,006
  2. 02Okawville1,347
  3. 03Centralia (part)8
Census Vintage 2024 subcounty estimates, county parts of incorporated places (SUMLEV 157).

Counties bordering Washington County

The Census 2024 county adjacency file lists 6 neighbors for Washington County. The most populous is St. Clair County, IL, with 251,149 residents. Distances run between Census internal points in a straight line.

Distance to Springfield and the nearest big city

Springfield is 99.4 miles N of Washington County's internal point in a straight line. The nearest place of 100,000 or more is St. Louis, MO (population 279,695), 48.8 miles away. The nearest place of 10,000 or more is Centralia, IL (population 11,787), 19.7 miles away.

Washington County FIPS code

The FIPS code of Washington County is 17189: state code 17 for Illinois plus county code 189. Use it as text, with the leading zero, when joining Census, BLS, or CDC county tables. SAIPE lists its 2023 median household income as $74,848.

Questions people ask

What is the population of Washington County, Illinois?

The Census Vintage 2024 estimate for July 1, 2024 is 13,535. That is down 196 people (1.4%) from the July 2020 estimate of 13,731.

What is the FIPS code of Washington County?

17189. The first two digits (17) are Illinois; the last three (189) identify the county.

What is the largest town in Washington County?

Nashville, with 3,006 residents inside Washington County in 2024.

Which counties border Washington County?

6 county-equivalents border it in the Census 2024 adjacency file: St. Clair County, IL; Clinton County, IL; Marion County, IL; Jefferson County, IL; Randolph County, IL; Perry County, IL.

Sources and data as of

Data as of: Census Vintage 2024 population estimates, 2024 Gazetteer land area and internal points, SAIPE 2023 median household income.

  1. 01Census Vintage 2024 county population estimates
  2. 02Census 2024 Gazetteer, counties
  3. 03Census SAIPE 2023 state and county estimates
  4. 04Census Vintage 2024 subcounty population estimates
  5. 05Census 2024 county adjacency file
  6. 06Census 2024 cartographic boundary file, counties (1:5,000,000)

How every number is computed: methodology. Spotted a wrong figure? Report an error.