According to theUS Census Bureau, the county has a total area of 417 square miles (1,080 km2), of which 416.4 square miles (1,078 km2) is land and 0.6 square miles (1.6 km2) (0.1%) is water.[5]
In recent years, average temperatures in the county seat of Tuscola have ranged from a low of 18 °F (−8 °C) in January to a high of 88 °F (31 °C) in July, although a record low of −26 °F (−32 °C) was recorded in December 1989 and a record high of 113 °F (45 °C) was recorded in July 1954. Average monthly precipitation ranged from 2.12 inches (54 mm) in February to 4.64 inches (118 mm) in July.[6]
As of the2020 census, the county had a population of 19,740. The median age was 39.6 years, 24.8% of residents were under the age of 18, and 18.8% of residents were 65 years of age or older. For every 100 females there were 97.8 males, and for every 100 females age 18 and over there were 95.1 males age 18 and over.[13]
25.0% of residents lived in urban areas, while 75.0% lived in rural areas.[15]
There were 7,749 households in the county, of which 31.1% had children under the age of 18 living in them. Of all households, 53.5% were married-couple households, 17.6% were households with a male householder and no spouse or partner present, and 23.1% were households with a female householder and no spouse or partner present. About 27.4% of all households were made up of individuals and 12.6% had someone living alone who was 65 years of age or older.[13]
There were 8,469 housing units, of which 8.5% were vacant. Among occupied housing units, 74.6% were owner-occupied and 25.4% were renter-occupied. The homeowner vacancy rate was 1.6% and the rental vacancy rate was 7.8%.[13]
Douglas 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.
As of the2010 United States census, there were 19,980 people, 7,720 households, and 5,377 families living in the county.[25] The population density was 48.0 inhabitants per square mile (18.5/km2). There were 8,390 housing units at an average density of 20.1 per square mile (7.8/km2).[5] The racial makeup of the county was 95.7% white, 0.4% Asian, 0.3% black or African American, 0.2% American Indian, 2.3% from other races, and 1.2% from two or more races. Those of Hispanic or Latino origin made up 6.1% of the population.[25] In terms of ancestry, 29.6% wereGerman, 12.6% wereAmerican, 12.1% wereEnglish, and 10.7% wereIrish.[26]
Of the 7,720 households, 32.6% had children under the age of 18 living with them, 57.0% were married couples living together, 8.5% had a female householder with no husband present, 30.3% were non-families, and 26.1% of all households were made up of individuals. The average household size was 2.57 and the average family size was 3.11. The median age was 38.7 years.[25]
The median income for a household in the county was $46,941 and the median income for a family was $60,352. Males had a median income of $41,318 versus $28,731 for females. The per capita income for the county was $21,438. About 7.1% of families and 10.2% of the population were below thepoverty line, including 14.0% of those under age 18 and 7.2% of those age 65 or over.[27]
Douglas is a strongly Republican county. Apart from a narrow plurality of thirty-two votes toBill Clinton in 1992, it has voted Republican in every Presidential election since 1968, and in all but five overall since 1880. Despite its long-time Republican leanings,Hillary Clinton's 2016 performance of gaining a mere 23.8 percent of the county's vote stands over six percent worse than any Democrat sincethe Civil War.
United States presidential election results for Douglas County, Illinois[28]