Rock Island County, Illinois

Last updated

Rock Island County
County
Rock Island County Justice Center.jpg
Rock Island County Justice Center
Rock Island County, Illinois logo.jpg
Logo
Map of Illinois highlighting Rock Island County.svg
Location within the U.S. state of Illinois
Illinois in United States.svg
Illinois's location within the U.S.
Coordinates: 41°28′N90°34′W / 41.47°N 90.57°W / 41.47; -90.57
CountryFlag of the United States.svg United States
StateFlag of Illinois.svg Illinois
Founded1831
Named after Rock (Arsenal) Island
Seat Rock Island
Largest city Moline
Area
 • Total
451 sq mi (1,170 km2)
 • Land428 sq mi (1,110 km2)
 • Water24 sq mi (60 km2)  5.2%
Population
 (2020)
 • Total
144,672
 • Estimate 
(2024)
142,731 Decrease2.svg [1]
 • Density320/sq mi (120/km2)
Time zone UTC−6 (Central)
 • Summer (DST) UTC−5 (CDT)
Congressional district 17th
Website rockislandcountyil.gov

Rock Island County is a county located in the U.S. state of Illinois, bounded on the west by the Mississippi River. According to the 2020 census, it had a population of 144,672. [2] Its county seat is Rock Island; its largest city is neighboring Moline. [3] Rock Island County is one of the four counties that make up the Davenport-Moline-Rock Island, IA-IL Metropolitan Statistical Area. [4]

Contents

History

Rock Island County at the time of its creation in 1831 Rock Island County Illinois 1831.png
Rock Island County at the time of its creation in 1831

Rock Island County was formed in 1831 out of Jo Daviess County. It was named for Rock Island, an island in the Mississippi River now known as Arsenal Island. [5] The Rock River (which the Sauk and Meskwaki peoples called Sinnissippi, meaning "rocky waters") [6] flows from Whiteside County and points further east and north and joins the Mississippi River at Rock Island. The Sinnissippi Mounds, dating from the Hopewell period and on the National Register of Historic Places are upriver at Sterling in Whiteside County.

Geography

According to the U.S. Census Bureau, the county has a total area of 451 square miles (1,170 km2), of which 428 square miles (1,110 km2) is land and 24 square miles (62 km2) (5.2%) is water. [7]

Climate and weather

Rock Island, Illinois
Climate chart (explanation)
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Source: The Weather Channel [8]
Metric conversion
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In recent years, average temperatures in the county seat of Rock Island have ranged from a low of 13 °F (−11 °C) in January to a high of 85 °F (29 °C) in July, although a record low of −22 °F (−30 °C) was recorded in February 1996 and a record high of 103 °F (39 °C) was recorded in July 2006. Average monthly precipitation ranged from 1.28 inches (33 mm) in January to 4.75 inches (121 mm) in June. [8]

Major highways

Transit

Adjacent counties

National protected area

Demographics

Historical population
CensusPop.Note%±
1840 2,610—
1850 6,937165.8%
1860 21,005202.8%
1870 29,78341.8%
1880 38,30228.6%
1890 41,9179.4%
1900 55,24931.8%
1910 70,40427.4%
1920 92,29731.1%
1930 98,1916.4%
1940 113,32315.4%
1950 133,55817.9%
1960 150,99113.1%
1970 166,73410.4%
1980 165,968−0.5%
1990 148,723−10.4%
2000 149,3740.4%
2010 147,546−1.2%
2020 144,672−1.9%
2023 (est.)141,236 [9] −2.4%
U.S. Decennial Census [10]
1790-1960 [11] 1900-1990 [12]
1990-2000 [13] 2010 [14]

2020 census

Rock Island County, Illinois – Racial and ethnic composition
Note: the US Census treats Hispanic/Latino as an ethnic category. This table excludes Latinos from the racial categories and assigns them to a separate category. Hispanics/Latinos may be of any race.
Race / Ethnicity (NH = Non-Hispanic)Pop 1980 [15] Pop 1990 [16] Pop 2000 [17] Pop 2010 [18] Pop 2020 [19] % 1980% 1990% 2000% 2010% 2020
White alone (NH)147,393128,986121,705111,76497,68988.81%86.73%81.48%75.75%67.52%
Black or African American alone (NH)9,71010,29011,09912,91116,1695.85%6.92%7.43%8.75%11.18%
Native American or Alaska Native alone (NH)2573012882832400.15%0.20%0.19%0.19%0.17%
Asian alone (NH)8899801,4992,3834,0330.54%0.66%1.00%1.62%2.79%
Native Hawaiian or Pacific Islander alone (NH)x [20] x [21] 344435xx0.02%0.03%0.02%
Other race alone (NH)510821091354820.31%0.06%0.07%0.09%0.33%
Mixed race or Multiracial (NH)x [22] x [23] 1,8492,9086,182xx1.24%1.97%4.27%
Hispanic or Latino (any race)7,2098,08412,79117,11819,8424.34%5.44%8.56%11.60%13.72%
Total165,968148,723149,374147,546144,672 100.00%100.00%100.00%100.00%100.00%

2010 census

As of the 2010 United States census, there were 147,546 people, 61,303 households, and 38,384 families residing in the county. [24] The population density was 345.0 inhabitants per square mile (133.2/km2). There were 65,756 housing units at an average density of 153.8 per square mile (59.4/km2). [7] The racial makeup of the county was 81.6% white, 9.0% black or African American, 1.6% Asian, 0.3% American Indian, 4.4% from other races, and 3.0% from two or more races. Those of Hispanic or Latino origin made up 11.6% of the population. [24] In terms of ancestry, 25.9% were German, 14.2% were Irish, 8.7% were English, 6.8% were Swedish, and 5.2% were American. [25]

Of the 61,303 households, 29.0% had children under the age of 18 living with them, 45.3% were married couples living together, 12.7% had a female householder with no husband present, 37.4% were non-families, and 31.6% of all households were made up of individuals. The average household size was 2.34 and the average family size was 2.93. The median age was 40.0 years. [24]

The median income for a household in the county was $46,226 and the median income for a family was $58,962. Males had a median income of $42,548 versus $31,917 for females. The per capita income for the county was $25,071. About 8.7% of families and 12.3% of the population were below the poverty line, including 19.0% of those under age 18 and 7.1% of those age 65 or over. [26]

Economy

At one time Mississippi Valley Airlines had its headquarters in Quad City Airport in the county. [27] John Deere is headquartered in Moline. [28]

Communities

Cities

Villages

Census-designated places

Townships

Rock Island County is divided into eighteen townships:

Forts

Politics

Before 1932, Rock Island County was a Republican stronghold in presidential elections, backing the party's candidate in every election from 1892 to 1928. From 1932 on, it has consistently backed Democratic Party presidential candidates, except for the national Republican landslides of 1952, 1956, 1972, and 1980. In 2016, Donald Trump managed to keep Hillary Clinton to a single-digit margin of victory, the first Republican to do so since Ronald Reagan in 1984; in 2020, Joe Biden increased the Democratic margin from 8.3% to 12.1%. Due to the dominance of the Democratic Party in county politics, Rock Island County remains one of the most Democratic counties outside of the Chicago area in Illinois. Since 2010 the Republican Party began making inroads in county politics, gaining a few seats on the Democratic-dominated county board; however, since 2018, the Republican Party influence on the board has begun to decrease as the county resumed heavy Democratic voting. [29]

United States presidential election results for Rock Island County, Illinois [30]
Year Republican Democratic Third party(ies)
No. %No. %No. %
1892 5,05252.38%4,03441.82%5595.80%
1896 7,32360.07%4,69238.49%1761.44%
1900 8,29961.22%4,78635.31%4713.47%
1904 8,15261.74%2,15616.33%2,89521.93%
1908 8,19655.45%4,73932.06%1,84612.49%
1912 6,50642.55%3,99726.14%4,78631.30%
1916 16,16953.17%10,91435.89%3,32710.94%
1920 21,90871.32%5,20816.95%3,60311.73%
1924 20,56357.69%3,63110.19%11,45332.13%
1928 27,24665.22%14,33434.31%1960.47%
1932 21,20545.55%24,67653.01%6681.44%
1936 19,48736.75%32,74161.74%7991.51%
1940 25,62941.95%35,24057.67%2320.38%
1944 23,98044.19%30,10255.48%1800.33%
1948 22,19247.01%24,54251.98%4771.01%
1952 32,93354.07%27,87945.77%1000.16%
1956 31,34251.72%29,14548.09%1180.19%
1960 32,53448.96%33,81250.88%1080.16%
1964 23,71436.22%41,75963.78%00.00%
1968 30,40443.35%34,50649.20%5,2307.46%
1972 37,54853.39%32,52946.25%2530.36%
1976 34,00747.72%35,99450.51%1,2601.77%
1980 34,78848.47%30,04541.86%6,9429.67%
1984 35,12146.41%40,20853.13%3430.45%
1988 27,41240.37%40,17459.17%3150.46%
1992 23,21232.22%37,41251.93%11,41515.85%
1996 20,62633.84%34,82257.13%5,5079.03%
2000 25,19438.70%37,95758.31%1,9442.99%
2004 29,66342.39%39,88056.99%4290.61%
2008 25,36436.97%42,21061.52%1,0341.51%
2012 24,93438.23%39,15760.04%1,1261.73%
2016 26,99842.19%32,29850.47%4,6987.34%
2020 28,60342.72%36,69154.81%1,6532.47%
2024 28,06144.07%34,12653.59%1,4922.34%

Education

K-12 school districts include: [31]

There is one secondary school district: United Township High School District 30. [31]

Elementary school districts include: [31]

See also

Footnotes

  1. ↑ "County Population Totals and Components of Change: 2020–2024". United States Census Bureau. U.S. Department of Commerce. March 2025. Retrieved August 31, 2025.
  2. ↑ "Rock Island County, Illinois". United States Census Bureau . Retrieved June 10, 2023.
  3. ↑ "Find a County". National Association of Counties. Archived from the original on May 31, 2011. Retrieved June 7, 2011.
  4. ↑ United States Office of Management and Budget. "Update of Statistical Area Definitions and Guidance on Their Uses" (PDF). pp. 5, 36. Archived from the original (PDF) on May 14, 2006. Retrieved July 21, 2006.
  5. ↑ Rock Island, the island, History: Introduction Archived January 14, 2009, at the Wayback Machine , US Army Corps of Engineers
  6. ↑ "Castle Rock State Park". Illinois DNR. Archived from the original on April 1, 2007. Retrieved August 3, 2014.
  7. 1 2 "Population, Housing Units, Area, and Density: 2010 - County". United States Census Bureau. Archived from the original on February 12, 2020. Retrieved July 12, 2015.
  8. 1 2 "Monthly Averages for Rock Island, Illinois". The Weather Channel. Archived from the original on November 12, 2009. Retrieved January 27, 2011.
  9. ↑ "Annual Estimates of the Resident Population for Counties: April 1, 2020 to July 1, 2023". United States Census Bureau. Retrieved April 2, 2024.
  10. ↑ "U.S. Decennial Census". United States Census Bureau. Retrieved July 8, 2014.
  11. ↑ "Historical Census Browser". University of Virginia Library. Archived from the original on August 11, 2012. Retrieved July 8, 2014.
  12. ↑ "Population of Counties by Decennial Census: 1900 to 1990". United States Census Bureau. Archived from the original on April 24, 2014. Retrieved July 8, 2014.
  13. ↑ "Census 2000 PHC-T-4. Ranking Tables for Counties: 1990 and 2000" (PDF). United States Census Bureau. Archived (PDF) from the original on December 18, 2014. Retrieved July 8, 2014.
  14. ↑ "State & County QuickFacts". United States Census Bureau. Archived from the original on June 7, 2011. Retrieved July 8, 2014.
  15. ↑ "1980 Census of Population - General Population Characteristics - Illinois- Table 14 - Persons by Race and Table 16 (p. 18-28) - Total Persons and Spanish Origin Persons by Type of Spanish Origin and Race (p. 29-39)" (PDF). United States Census Bureau .
  16. ↑ "1990 Census of Population - General Population Characteristics - Illinois - Table 6 - Race and Hispanic Orogin" (PDF). United States Census Bureau .
  17. ↑ "P004: Hispanic or Latino, and Not Hispanic or Latino by Race – 2000: DEC Summary File 1 – Rock Island County, Illinois". United States Census Bureau .
  18. ↑ "P2: Hispanic or Latino, and Not Hispanic or Latino by Race – 2010: DEC Redistricting Data (PL 94-171) – Rock Island County, Illinois". United States Census Bureau .
  19. ↑ "P2: Hispanic or Latino, and Not Hispanic or Latino by Race – 2020: DEC Redistricting Data (PL 94-171) – Rock Island County, Illinois". United States Census Bureau .
  20. ↑ included in the Asian category in the 1980 Census
  21. ↑ included in the Asian category in the 1990 Census
  22. ↑ not an option in the 1980 Census
  23. ↑ not an option in the 1990 Census
  24. 1 2 3 "DP-1 Profile of General Population and Housing Characteristics: 2010 Demographic Profile Data". United States Census Bureau. Archived from the original on February 13, 2020. Retrieved July 12, 2015.
  25. ↑ "DP02 SELECTED SOCIAL CHARACTERISTICS IN THE UNITED STATES – 2006-2010 American Community Survey 5-Year Estimates". United States Census Bureau. Archived from the original on February 13, 2020. Retrieved July 12, 2015.
  26. ↑ "DP03 SELECTED ECONOMIC CHARACTERISTICS – 2006-2010 American Community Survey 5-Year Estimates". United States Census Bureau. Archived from the original on February 13, 2020. Retrieved July 12, 2015.
  27. ↑ "World Airline Directory." Flight International . March 30, 1985. 98 Archived February 23, 2013, at the Wayback Machine . "Head Office: PO Box 949, Quad City Airport, Moline, Illinois 61265, USA."
  28. ↑ "Deere & Company World Headquarters" . Retrieved March 21, 2019.
  29. ↑ "Rock Island County Clerk - Elections - Previous Election Results".
  30. ↑ Leip, David. "Dave Leip's Atlas of U.S. Presidential Elections". uselectionatlas.org. Archived from the original on March 23, 2018. Retrieved May 6, 2018.
  31. 1 2 3 Geography Division (December 22, 2020). 2020 CENSUS - SCHOOL DISTRICT REFERENCE MAP: Rock Island County, IL (PDF) (Map). U.S. Census Bureau . Retrieved June 15, 2025. - Text list

Further reading

41°28′N90°34′W / 41.47°N 90.57°W / 41.47; -90.57

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