• county
  • FIPS 17087
  • Largest town: Vienna

Johnson County, Illinois

Johnson County had 13,320 residents in the Census Vintage 2024 estimate, on 343.7 square miles of land. It ranks 79th of 102 in Illinois by population and 85th by land area.

Population
13,320
#79 of 102 in Illinois · #2,203 in US
Area
343.7 sq mi
#85 of 102 in Illinois · #2,698 in US
Density
39 / sq mi
#60 of 102 in Illinois · #1,700 in US
Median household income
$63,160
#67 of 102 in Illinois · #1,545 in US

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

Johnson County within Illinois. Pin: Springfield.

Measure from here

Tools and pages that start from Johnson County

Johnson County population, land area and income

Johnson County had 13,320 residents in the Census Vintage 2024 estimate, on 343.7 square miles of land. It ranks 79th of 102 in Illinois by population and 85th by land area. That works out to 38.8 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; Johnson County is somewhat smaller.

Its SAIPE 2023 median household income of $63,160 is above the national county median among 3,143 counties with an estimate.

National rank among 3,144

Population

13,320

3144th1st

2203rd of 3,144 (US)

Land area

344 sq mi

3144th1st

2698th of 3,144 (US)

Density

38.8 / sq mi

3144th1st

1700th of 3,144 (US)

Median household income

$63,160

3143rd1st

1545th of 3,143 (US)

Rank within Illinois (102)

Population

13,320

102nd1st

79th of 102 (IL)

Land area

344 sq mi

102nd1st

85th of 102 (IL)

Density

38.8 / sq mi

102nd1st

60th of 102 (IL)

Median household income

$63,160

102nd1st

67th of 102 (IL)

How Johnson County's population changed since 2020

Johnson County lost 2 residents between the July 2020 and July 2024 estimates, a drop of 0.0%. That ranks 16th 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, Johnson County recorded 456 births and 701 deaths, a natural change of -245. Net international migration added +39 and net domestic migration, people moving to or from other US counties, came to +231. The largest single component was natural change, which removed 245 people.

13.3k202013.5k202113.4k202213.4k202313.3k2024
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
456
Deaths
701
Net international migration
+39
Net domestic migration
+231
Change, July 2023 to July 2024
-35

Where Johnson County is

The Census internal point of Johnson County is at 37.460700, -88.882100. 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 Johnson 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: Johnson County internal point. Dark pin: Springfield.

Internal point

Decimal
37.460700, -88.882100
DMS
37°27'38.52"N 88°52'55.56"W
UTM
16N 333546.0E 4147644.5N
Geohash
dn8v17w02
Plus code
869HF469+75

Towns in Johnson County

2 incorporated places of 1,000+ people have residents in Johnson County, 2,404 people together, or 18% of the county. Each figure counts only the part of the town inside Johnson County; towns marked "part" extend into another county. The largest is Vienna with 1,350.

  1. 01Vienna1,350
  2. 02Goreville1,054
Census Vintage 2024 subcounty estimates, county parts of incorporated places (SUMLEV 157).

Counties bordering Johnson County

The Census 2024 county adjacency file lists 6 neighbors for Johnson County. The most populous is Williamson County, IL, with 67,064 residents. Distances run between Census internal points in a straight line.

Distance to Springfield and the nearest big city

Springfield is 165.6 miles NNW of Johnson County's internal point in a straight line. The nearest place of 100,000 or more is Evansville, IN (population 115,395), 82.1 miles away. The nearest place of 10,000 or more is Marion, IL (population 17,021), 19.2 miles away.

Johnson County FIPS code

The FIPS code of Johnson County is 17087: state code 17 for Illinois plus county code 087. Use it as text, with the leading zero, when joining Census, BLS, or CDC county tables. SAIPE lists its 2023 median household income as $63,160.

Questions people ask

What is the population of Johnson County, Illinois?

The Census Vintage 2024 estimate for July 1, 2024 is 13,320. That is down 2 people (0.0%) from the July 2020 estimate of 13,322.

What is the FIPS code of Johnson County?

17087. The first two digits (17) are Illinois; the last three (087) identify the county.

What is the largest town in Johnson County?

Vienna, with 1,350 residents inside Johnson County in 2024.

Which counties border Johnson County?

6 county-equivalents border it in the Census 2024 adjacency file: Williamson County, IL; Saline County, IL; Union County, IL; Massac County, IL; Pulaski County, IL; Pope 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.