During the Civil War, the county was a Southern Unionist bastion, voting against secession from the Union in Tennessee's June 1861 referendum by a higher percentage than in any other Tennessee county. This sentiment was encouraged by a June 4, 1861, speech in Huntsville by U.S. Senator Andrew Johnson. In 1861, the county assembly officially enacted a resolution seceding from the state of Tennessee, and thus the Confederacy, forming the "Free and Independent State of Scott," also known simply as the "State of Scott." The county remained a pro-Union enclave throughout the war. Ulysses S. Grant received over 90% of the vote in Scott County during both the 1868 United States presidential election and the 1872 United States presidential election. The proclamation was finally repealed, over a hundred years later, by Scott County in 1986.
At the 2000 census, there were 21,127 people, 8,203 households and 6,012 families residing in the county. The population density was 40 per square mile. There were 8,909 housing units at an average density of 17 per square mile. The racial makeup of the county was 98.53% White, 0.09% Black or African American, 0.25% Native American, 0.12% Asian, 0.10% from other races, and 0.91% from two or more races. 0.57% of the population were Hispanic or Latino of any race. There were 8,203 households of which 35.70% had children under the age of 18 living with them, 57.20% were married couples living together, 11.80% had a female householder with no husband present, and 26.70% were non-families. 24.30% of all households were made up of individuals and 9.50% had someone living alone who was 65 years of age or older. The average household size was 2.55 and the average family size was 3.02. 26.10% of the population were under the age of 18, 10.30% from 18 to 24, 28.70% from 25 to 44, 23.60% from 45 to 64, and 11.30% who were 65 years of age or older. The median age was 35 years. For every 100 females there were 97.40 males. For every 100 females age 18 and over, there were 94.00 males. The median household income was $24,093 and the median family income was $28,595. Males had a median income of $24,721 compared with $19,451 for females. The per capita income for the county was $12,927. About 17.60% of families and 20.20% of the population were below the poverty line, including 24.10% of those under age 18 and 17.10% of those age 65 or over. Scott County, a part of the Cumberland Plateau, includes the majority of the Big South Fork National River and Recreation Area.
2010 ancestry
As of 2010, the largest self-reported ancestry groups in the county were:
Includes the Scott County Sheriff Department; Oneida and Winfield Police Department; a full-time ambulance service with two stations; a volunteer rescue squad; and nine volunteer fire stations placed throughout the county.
