State Route 30 - The principal east/west highway. This highway divides the county into north and south and intersects Highway 58 in Decatur. The Tennessee Department of Transportation is in the process of upgrading Highway 30 from a 2-lane highway to a 4-lane divided highway. allowing for more major east/west traffic and faster connection to Interstate 75.
State Route 60 - A principal east/west highway forming the southern border of the county.
State Route 304 - An important local road, mainly for local residents that live off of the highway, and its northern portions allows access to Watts Bar Lake's many marinas, resorts, and campgrounds. Also connects the unincorporated community of Ten Mile with the county seat of Decatur.
State Route 305 - An important local road, connecting Interstate 75 with State Route 68 and State Route 58. This also connects the north-central part of the county with the neighboring city of Athens in McMinn County.
As of the census of 2000, there were 11,086 people, 4,304 households, and 3,262 families residing in the county. The population density was 57 people per square mile (22/km²). There were 5,188 housing units at an average density of 27 per square mile (10/km²). The racial makeup of the county was 97.65% White, 1.24% Black or African American, 0.21% Native American, 0.18% Asian, 0.11% from other races, and 0.60% from two or more races. 0.57% of the population were Hispanic or Latino of any race.
There were 4,304 households out of which 32.80% had children under the age of 18 living with them, 61.70% were married couples living together, 9.90% had a female householder with no husband present, and 24.20% were non-families. 20.80% of all households were made up of individuals and 7.80% 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 2.94.
In the county the population was spread out with 25.10% under the age of 18, 8.10% from 18 to 24, 28.90% from 25 to 44, 26.30% from 45 to 64, and 11.50% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 100.00 males. For every 100 females age 18 and over, there were 97.30 males.
The median income for a household in the county was $29,354, and the median income for a family was $34,114. Males had a median income of $29,521 versus $20,419 for females. The per capita income for the county was $14,551. About 15.80% of families and 18.30% of the population were below the poverty line, including 23.50% of those under age 18 and 14.60% of those age 65 or over.