Rock Island County, Illinois

"Rock Island County" redirects here. Not to be confused with Rock Island Township.

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.^[1] Its county seat is Rock Island; its largest city is neighboring Moline.^[2] Rock Island County is one of the four counties that make up the Davenport-Moline-Rock Island, IA-IL Metropolitan Statistical Area.^[3]

Rock Island County
County
Rock Island County Justice Center
Logo
Location within the U.S. state of Illinois
Illinois's location within the U.S.
Coordinates: 41°28′N 90°34′W
Country	United States
State	Illinois
Founded	1831
Named for	Rock (Arsenal) Island
Seat	Rock Island
Largest city	Moline
Area
• Total	451 sq mi (1,170 km2)
• Land	428 sq mi (1,110 km2)
• Water	24 sq mi (60 km2)  5.2%
Population  (2020)
• Total	144,672
• Estimate  (2023)	141,236
• Density	320/sq mi (120/km2)
Time zone	UTC−6 (Central)
• Summer (DST)	UTC−5 (CDT)
Congressional district	17th
Website	rockislandcountyil.gov

History

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.^[4] The Rock River (which the Sauk and Meskwaki peoples called Sinnissippi, meaning "rocky waters")^[5] 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.^[6]

Climate and weather

Rock Island, Illinois
Climate chart (explanation)
J F M A M J J A S O N D     1.3     30 13     1.4     36 19     2.6     48 29     3.6     61 41     4.4     72 52     4.8     81 63     3     85 68     4.3     83 66     2.9     76 57     2.4     65 45     2.5     48 32     1.9     35 20 █ Average max. and min. temperatures in °F █ Precipitation totals in inches Source: The Weather Channel[7]
Metric conversion J F M A M J J A S O N D     33     −1 −11     36     2 −7     66     9 −2     92     16 5     113     22 11     121     27 17     76     29 20     109     28 19     74     24 14     61     18 7     63     9 0     49     2 −7 █ Average max. and min. temperatures in °C █ Precipitation totals in mm

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.^[7]

Major highways

• Interstate 74
• Interstate 80
• Interstate 88
• Interstate 280
• U.S. Highway 6
• U.S. Highway 67
• U.S. Highway 150
• Illinois Route 2 (formerly)
• Illinois Route 5
• Illinois Route 84
• Illinois Route 92
• Illinois Route 94
• Illinois Route 110
• Illinois Route 192

Transit

• Quad Cities MetroLINK
• List of intercity bus stops in Illinois

Adjacent counties

• Clinton County, Iowa (north)
• Whiteside County (northeast)
• Henry County (southeast)
• Mercer County (south)
• Louisa County, Iowa (southwest)
• Muscatine County, Iowa (west)
• Scott County, Iowa (northwest)

National protected area

• Upper Mississippi River National Wildlife and Fish Refuge (part)

Demographics

Historical population

Census	Pop.	Note	%±
1840	2,610		—
1850	6,937		165.8%
1860	21,005		202.8%
1870	29,783		41.8%
1880	38,302		28.6%
1890	41,917		9.4%
1900	55,249		31.8%
1910	70,404		27.4%
1920	92,297		31.1%
1930	98,191		6.4%
1940	113,323		15.4%
1950	133,558		17.9%
1960	150,991		13.1%
1970	166,734		10.4%
1980	165,968		−0.5%
1990	148,723		−10.4%
2000	149,374		0.4%
2010	147,546		−1.2%
2020	144,672		−1.9%
2023 (est.)	141,236	[8]	−2.4%
U.S. Decennial Census[9] 1790-1960[10] 1900-1990[11] 1990-2000[12] 2010[13]

As of the 2010 United States Census, there were 147,546 people, 61,303 households, and 38,384 families residing in the county.^[14] 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).^[6] 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.^[14] 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.^[15]

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.^[14]

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.^[16]

Economy

At one time Mississippi Valley Airlines had its headquarters in Quad City Airport in the county.^[17] John Deere is headquartered in Moline.^[18]

Communities

Cities

• East Moline
• Moline
• Rock Island
• Silvis

Villages

• Andalusia
• Carbon Cliff
• Coal Valley (part)
• Cordova
• Hampton
• Hillsdale
• Milan
• Oak Grove
• Port Byron
• Rapids City
• Reynolds (part)

Census-designated places

• Coyne Center
• Rock Island Arsenal

Unincorporated communities

• Barstow
• Buffalo Prairie
• Campbell's Island
• Edgington
• Illinois City
• Joslin
• Taylor Ridge

Townships

Rock Island County is divided into eighteen townships:

• Andalusia
• Blackhawk
• Bowling
• Buffalo Prairie
• Canoe Creek
• Coal Valley
• Coe
• Cordova
• Drury
• Edgington
• Hampton
• Moline
• Port Byron
• Rock Island
• Rural
• South Moline
• South Rock Island
• Zuma

Forts

• Fort Armstrong

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.^[19]

United States presidential election results for Rock Island County, Illinois^[20]

Year	Republican		Democratic		Third party(ies)
	No.	%	No.	%	No.	%
2020	28,603	42.72%	36,691	54.81%	1,653	2.47%
2016	26,998	42.19%	32,298	50.47%	4,698	7.34%
2012	24,934	38.23%	39,157	60.04%	1,126	1.73%
2008	25,364	36.97%	42,210	61.52%	1,034	1.51%
2004	29,663	42.39%	39,880	56.99%	429	0.61%
2000	25,194	38.70%	37,957	58.31%	1,944	2.99%
1996	20,626	33.84%	34,822	57.13%	5,507	9.03%
1992	23,212	32.22%	37,412	51.93%	11,415	15.85%
1988	27,412	40.37%	40,174	59.17%	315	0.46%
1984	35,121	46.41%	40,208	53.13%	343	0.45%
1980	34,788	48.47%	30,045	41.86%	6,942	9.67%
1976	34,007	47.72%	35,994	50.51%	1,260	1.77%
1972	37,548	53.39%	32,529	46.25%	253	0.36%
1968	30,404	43.35%	34,506	49.20%	5,230	7.46%
1964	23,714	36.22%	41,759	63.78%	0	0.00%
1960	32,534	48.96%	33,812	50.88%	108	0.16%
1956	31,342	51.72%	29,145	48.09%	118	0.19%
1952	32,933	54.07%	27,879	45.77%	100	0.16%
1948	22,192	47.01%	24,542	51.98%	477	1.01%
1944	23,980	44.19%	30,102	55.48%	180	0.33%
1940	25,629	41.95%	35,240	57.67%	232	0.38%
1936	19,487	36.75%	32,741	61.74%	799	1.51%
1932	21,205	45.55%	24,676	53.01%	668	1.44%
1928	27,246	65.22%	14,334	34.31%	196	0.47%
1924	20,563	57.69%	3,631	10.19%	11,453	32.13%
1920	21,908	71.32%	5,208	16.95%	3,603	11.73%
1916	16,169	53.17%	10,914	35.89%	3,327	10.94%
1912	6,506	42.55%	3,997	26.14%	4,786	31.30%
1908	8,196	55.45%	4,739	32.06%	1,846	12.49%
1904	8,152	61.74%	2,156	16.33%	2,895	21.93%
1900	8,299	61.22%	4,786	35.31%	471	3.47%
1896	7,323	60.07%	4,692	38.49%	176	1.44%
1892	5,052	52.38%	4,034	41.82%	559	5.80%

See also

• National Register of Historic Places listings in Rock Island County, Illinois
• Quad Cities International Airport

Footnotes

1. "Rock Island County, Illinois". United States Census Bureau. Retrieved June 10, 2023.
2. "Find a County". National Association of Counties. Archived from the original on May 31, 2011. Retrieved June 7, 2011.
3. 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.
4. Rock Island, the island, History: Introduction Archived January 14, 2009, at the Wayback Machine, US Army Corps of Engineers
5. "Castle Rock State Park". Illinois DNR. Archived from the original on April 1, 2007. Retrieved August 3, 2014.
6. "Population, Housing Units, Area, and Density: 2010 - County". United States Census Bureau. Archived from the original on February 12, 2020. Retrieved July 12, 2015.
7. "Monthly Averages for Rock Island, Illinois". The Weather Channel. Archived from the original on November 12, 2009. Retrieved January 27, 2011.
8. "Annual Estimates of the Resident Population for Counties: April 1, 2020 to July 1, 2023". United States Census Bureau. Retrieved April 2, 2024.
9. "U.S. Decennial Census". United States Census Bureau. Retrieved July 8, 2014.
10. "Historical Census Browser". University of Virginia Library. Archived from the original on August 11, 2012. Retrieved July 8, 2014.
11. "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.
12. "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.
13. "State & County QuickFacts". United States Census Bureau. Archived from the original on June 7, 2011. Retrieved July 8, 2014.
14. "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.
15. "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.
16. "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.
17. "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."
18. "Deere & Company World Headquarters". Retrieved March 21, 2019.
19. "Rock Island County Clerk - Elections - Previous Election Results".
20. 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.

Further reading

• Portrait and Biographical Album of Rock Island County, Illinois: Containing Full-Page Portraits and Biographical Sketches of Prominent and Representative Citizens of the County, Together with Portraits and Biographies of All the Governors of Illinois, and of the Presidents of the United States; Also Containing a History of the County, from its Earliest Settlement to the Present Time. Chicago: Biographical Publishing Co., 1885.

External links

• Official county website
• Rock Island County Historical Society

41.47°N 90.57°W / 41.47; -90.57