• county
  • FIPS 17161
  • Largest town: Moline

Rock Island County, Illinois

Rock Island County had 142,731 residents in the Census Vintage 2024 estimate, on 427.5 square miles of land. It ranks 15th of 102 in Illinois by population and 67th by land area.

Population
142,731
#15 of 102 in Illinois · #476 in US
Area
427.5 sq mi
#67 of 102 in Illinois · #2,376 in US
Density
334 / sq mi
#11 of 102 in Illinois · #398 in US
Median household income
$63,457
#64 of 102 in Illinois · #1,517 in US

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

Rock Island County within Illinois. Pin: Springfield.

Measure from here

Tools and pages that start from Rock Island County

Rock Island County population, land area and income

Rock Island County had 142,731 residents in the Census Vintage 2024 estimate, on 427.5 square miles of land. It ranks 15th of 102 in Illinois by population and 67th by land area. That works out to 333.9 people per square mile, 3.5 times the US average of 96.3, and in the top quarter nationally.

The median county-equivalent in Illinois has 24,447 residents, so Rock Island County is 5.8 times that size.

Its SAIPE 2023 median household income of $63,457 is above the national county median among 3,143 counties with an estimate.

National rank among 3,144

Population

142,731

3144th1st

476th of 3,144 (US)

Land area

428 sq mi

3144th1st

2376th of 3,144 (US)

Density

333.9 / sq mi

3144th1st

398th of 3,144 (US)

Median household income

$63,457

3143rd1st

1517th of 3,143 (US)

Rank within Illinois (102)

Population

142,731

102nd1st

15th of 102 (IL)

Land area

428 sq mi

102nd1st

67th of 102 (IL)

Density

333.9 / sq mi

102nd1st

11th of 102 (IL)

Median household income

$63,457

102nd1st

64th of 102 (IL)

How Rock Island County's population changed since 2020

Rock Island County lost 1,629 residents between the July 2020 and July 2024 estimates, a drop of 1.1%. That ranks 35th 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, Rock Island County recorded 6,569 births and 7,522 deaths, a natural change of -953. Net international migration added +3,091 and net domestic migration, people moving to or from other US counties, came to -4,087. The largest single component was domestic migration, which removed 4,087 people.

144.4k2020142.9k2021141.8k2022141.9k2023142.7k2024
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
6,569
Deaths
7,522
Net international migration
+3,091
Net domestic migration
-4,087
Change, July 2023 to July 2024
+792

Where Rock Island County is

The Census internal point of Rock Island County is at 41.468400, -90.572100. It sits in UTM zone 15N. The map shades Illinois's 102 county-equivalents by population change from 2020 to 2024, darker for faster growth, with Rock Island 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: Rock Island County internal point. Dark pin: Springfield.

Internal point

Decimal
41.468400, -90.572100
DMS
41°28'6.24"N 90°34'19.56"W
UTM
15N 702745.3E 4593601.5N
Geohash
9zrefvp6v
Plus code
86HFFC9H+95

Towns in Rock Island County

10 incorporated places of 1,000+ people have residents in Rock Island County, 122,990 people together, or 86% of the county. Each figure counts only the part of the town inside Rock Island County; towns marked "part" extend into another county. The largest is Moline with 42,442.

  1. 01Moline42,442
  2. 02Rock Island36,434
  3. 03East Moline20,995
  4. 04Silvis8,003
  5. 05Milan5,033
  6. 06Coal Valley (part)3,710
  7. 07Carbon Cliff1,808
  8. 08Hampton1,755
  9. 09Port Byron1,643
  10. 10Andalusia1,167
Census Vintage 2024 subcounty estimates, county parts of incorporated places (SUMLEV 157).

Counties bordering Rock Island County

The Census 2024 county adjacency file lists 7 neighbors for Rock Island County, including 4 across a state line. The most populous is Scott County, IA, with 175,601 residents. Distances run between Census internal points in a straight line.

Distance to Springfield and the nearest big city

Springfield is 126.2 miles SSE of Rock Island County's internal point in a straight line. The nearest place of 100,000 or more is Davenport, IA (population 100,938), 6.3 miles away. The nearest place of 10,000 or more is Rock Island, IL (population 36,434), 0.7 miles away.

Rock Island County FIPS code

The FIPS code of Rock Island County is 17161: state code 17 for Illinois plus county code 161. Use it as text, with the leading zero, when joining Census, BLS, or CDC county tables. SAIPE lists its 2023 median household income as $63,457.

Questions people ask

What is the population of Rock Island County, Illinois?

The Census Vintage 2024 estimate for July 1, 2024 is 142,731. That is down 1,629 people (1.1%) from the July 2020 estimate of 144,360.

What is the FIPS code of Rock Island County?

17161. The first two digits (17) are Illinois; the last three (161) identify the county.

What is the largest town in Rock Island County?

Moline, with 42,442 residents inside Rock Island County in 2024.

Which counties border Rock Island County?

7 county-equivalents border it in the Census 2024 adjacency file: Scott County, IA; Whiteside County, IL; Henry County, IL; Clinton County, IA; Muscatine County, IA; Mercer County, IL; Louisa County, IA.

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.