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 2010 census, it had a population of 147,546. Its county seat is Rock Island; its largest city is neighboring Moline.
According to the U.S. Census Bureau, the county has a total area of 451 square miles (1,170 km), of which 428 square miles (1,110 km) is land and 24 square miles (62 km) (5.2%) is water.
As of the 2010 United States Census, there were 147,546 people, 61,303 households, and 38,384 families residing in the county. The population density was 345.0 inhabitants per square mile (133.2/km). There were 65,756 housing units at an average density of 153.8 per square mile (59.4/km). 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. 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.
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.
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.
Rock Island County Illinois neighborhoods include: 23rd Ave, 35th and 35th, 38th and 38th, Arsenal Gateway, Audubon, Broadway District, East Central / 45th ST, Eugene Field, French Farms, Greenbush, Highland Park, Hill Top, Keystone, Longview, Rock Island/Milan Border, Salem Court, Saukie, W Rock Island