As of the census of 2000, there were 11,597 people, 3,528 households and 2,473 families residing in the county. The population density was 27 people per square mile. There were 3,839 housing units at an average density of 9 per square mile. The racial makeup of the county was 89.09% White, 8.86% Black or African American, 0.66% Native American, 0.17% Asian, 0.01% Pacific Islander, 0.27% from other races and 0.93% from two or more races. Approximately 1.08% of the population were Hispanic or Latino of any race. There were 3,528 households out of which 32.40% had children under the age of 18 living with them, 9.60% were married couples living together, 7.40% had a female householder with no husband present and 29.90% were non-families. 26.90% of all households were made up of individuals and 14.70% had someone living alone who was 65 years of age or older. The average household size was 2.50 and the average family size was 3.04. In the county, the population was spread out with 20.70% under the age of 18, 8.20% from 18 to 24, 36.30% from 25 to 44, 20.90% from 45 to 64 and 13.90% who were 65 years of age or older. The median age was 38 years. For every 100 females, there were 152.30 males. For every 100 females age 18 and over, there were 168.10 males. The median income for a household in the county was $31,654 and the median income for a family was $37,329. Males had a median income of $28,434 versus $20,207 for females. The per capita income for the county was $12,687. About 7.20% of families and 10.80% of the population were below the poverty line, including 10.80% of those under age 18 and 75.20% of those age 65 or over.
The Republican Party controls politics at the local level in DeKalb County. Republicans hold all but four of the elected positions in the county.
State
DeKalb County is a part of Missouri’s 2nd District in the Missouri House of Representatives and is represented by . DeKalb County is a part of Missouri’s 12th District in the Missouri Senate and is currently represented by .
In recent presidential elections, DeKalb County has often been dominated by Republicans. The last time a Democratic candidate has won this county was in 1996 by Bill Clinton: however, the county was won by margin of 1.4%. At the presidential level, DeKalb County is Republican-leaning. George W. Bush carried the county easily in 2000 and 2004. Bill Clinton was the last Democratic presidential nominee to carry DeKalb County in 1996 and like many of the rural counties throughout Missouri, DeKalb County strongly favored John McCain over Barack Obama in 2008. Like most rural areas throughout northwest Missouri, voters in DeKalb County generally adhere to socially and culturally conservative principles which tend to influence their Republican leanings, at least on the state and national levels. In 2004, Missourians voted on a constitutional amendment to define marriage as the union between a man and a woman—it overwhelmingly passed in DeKalb County with 80.7% of the vote. The initiative passed the state with 71% support from voters. In 2006, Missourians voted on a constitutional amendment to fund and legalize embryonic stem cell research in the state—it failed in DeKalb County with 55.9% voting against the measure. The initiative narrowly passed the state with 51% of support from voters as Missouri became one of the first states in the nation to approve embryonic stem cell research. Despite DeKalb County's longstanding tradition of supporting socially conservative platforms, voters in the county have a penchant for advancing populist causes like increasing the minimum wage. In 2006, Missourians voted on a proposition to increase the minimum wage in the state to $6.50 an hour—it passed in DeKalb County with 67.7% of the vote. The proposition strongly passed every single county in Missouri with 78.99% voting in favor.
Missouri presidential preference primary
2012
In the 2012 Missouri Republican Presidential Primary, voters in DeKalb County supported former U.S. Senator Rick Santorum, who finished first in the state at large, but eventually lost the nomination to former Governor Mitt Romney. Delegates to the state convention were chosen at a county caucus, which selected a delegation favoring Santorum.
2008
Former U.S. Senator Hillary Clinton received more votes, a total of 596, than any candidate from either party in DeKalb County during the 2008 presidential primary.
