This area was long occupied by varying cultures of Native Americans. Whiteside County was organized by European Americans in 1836 from parts of Jo Daviess and Henry counties. It was named for General Samuel Whiteside, an Illinois officer in the War of 1812 and Black Hawk War.
Geography
According to the U.S. Census Bureau, the county has a total area of, of which is land and is water.
Climate and weather
In recent years, average temperatures in the county seat of Morrison have ranged from a low of in January to a high of in July, although a record low of was recorded in February 1905 and a record high of was recorded in July 1936. Average monthly precipitation ranged from in February to in August.
As of the 2010 United States Census, there were 58,498 people, 23,740 households, and 16,005 families residing in the county. The population density was. There were 25,770 housing units at an average density of. The racial makeup of the county was 92.2% white, 1.3% black or African American, 0.5% Asian, 0.3% American Indian, 3.5% from other races, and 2.2% from two or more races. Those of Hispanic or Latino origin made up 11.0% of the population. In terms of ancestry, 32.5% were German, 15.5% were Irish, 8.7% were Dutch, 8.6% were English, and 6.0% were American. Of the 23,740 households, 30.4% had children under the age of 18 living with them, 51.5% were married couples living together, 11.0% had a female householder with no husband present, 32.6% were non-families, and 27.7% of all households were made up of individuals. The average household size was 2.42 and the average family size was 2.92. The median age was 41.8 years. The median income for a household in the county was $45,266 and the median income for a family was $54,242. Males had a median income of $41,862 versus $29,157 for females. The per capita income for the county was $23,405. About 8.2% of families and 11.2% of the population were below the poverty line, including 17.6% of those under age 18 and 5.8% of those age 65 or over.
Whiteside County has a political history typical of Northern Illinois. Between its first election in 1840, and 1852, it always favored the Whig Party, and although Whiteside was not as strong for the Free Soil Party as counties to the east like Boone and Lake, it gave substantial votes to that party in 1848 and 1852 and became powerfully Republican for the next century-and-a-quarter. Between 1856 and 1988 the only time Whiteside County did not vote for the Republican candidate was in 1912 when the GOP was mortally divided and Whiteside County voted for Progressive Party nominee and former President Theodore Roosevelt over conservative incumbent William Howard Taft. Between at least 1880 and 1960, no Democratic Presidential nominee ever won forty percent of Whiteside County's vote, and even Alf Landon in 1936 carried the county by 22 percent when losing 46 of 48 states. In 1964 the Republican Party nominated Barry Goldwater, whose hostility to the Yankee establishment and strongly conservative policies were sufficient to leave many traditional Republicans to stay home or even to vote for Lyndon Johnson, who lost the county only by 404 votes out of over twenty-five thousand. The county returned to solid Republican voting for the next twenty years, but, ironically when its most famous native came within 3,818 votes of sweeping all fifty states, actually voted marginally more Democratic than the nation at-large in 1984, repeated this in 1988 and voted Democratic for the first time in its history by giving a plurality to Bill Clinton in 1992. The county would give its first-ever Democratic majority to president Clinton in 1996 and continue to vote Democratic until 2016, when concern over employment declines in the “Rust Belt“ saw Donald Trump become the first Republican to carry the county since George H. W. Bush.
