According to the U.S. Census Bureau, the county has a total area of, of which is land and is water. All of the county's northern border faces Indiana, across from the Ohio River.
The Regional planning group One Knox considers the largest road projects needed to support the growth from the BRAC realignment at Fort Knox to include extending Kentucky Route 313 to US 60 in Meade County and then into Brandenburg creating a corridor between Radcliff and Elizabethtown running parallel to U.S. Route 31W, and building a new extension from Bullion Boulevard in Fort Knox to KY 313 in Radcliff. The group estimates that buying the right of way for the KY 313 project to Brandenburg would cost nearly $30 million. The realignment at Fort Knox is projected to bring thousands of workers and jobs, along with millions of dollars into the regions economy.
As of the census of 2000, there were 26,349 people, 9,470 households, and 7,396 families residing in the county. The population density was. There were 10,293 housing units at an average density of. The racial makeup of the county was 92.37% White, 4.13% Black or African American, 0.59% Native American, 0.53% Asian, 0.13% Pacific Islander, 0.83% from other races, and 1.43% from two or more races. 2.15% of the population were Hispanic or Latino of any race. There were 9,470 households out of which 42.20% had children under the age of 18 living with them, 64.10% were married couplesliving together, 9.70% had a female householder with no husband present, and 21.90% were non-families. Of all households 18.40% were made up of individuals and 6.50% had someone living alone who was 65 years of age or older. The average household size was 2.77 and the average family size was 3.15. In the county, the population was spread out with 29.80% under the age of 18, 9.10% from 18 to 24, 32.70% from 25 to 44, 20.30% from 45 to 64, and 8.10% who were 65 years of age or older. The median age was 32 years. For every 100 females, there were 100.40 males. For every 100 females age 18 and over, there were 98.30 males. The median income for a household in the county was $36,966, and the median income for a family was $40,592. Males had a median income of $30,835 versus $22,038 for females. The per capita income for the county was $16,000. About 9.30% of families and 11.30% of the population were below the poverty line, including 13.80% of those under age 18 and 12.30% of those age 65 or over.
