The terrain of Holt County consists of low rolling hills, with the flattened areas used for agriculture. The Niobrara River flows eastward along the north line of the county, and the Elkhorn River flows southeastward through the upper central portion of the county. The county has an area of, of which is land and is water. It is Nebraska's fifth-largest county by area.
As of the 2000 United States Census, there were 11,551 people, 4,608 households, and 3,170 families residing in the county. The population density was 5 people per square mile. There were 5,281 housing units at an average density of 2 per square mile. The racial makeup of the county was 98.86% White, 0.03% Black or African American, 0.29% Native American, 0.18% Asian, 0.05% Pacific Islander, 0.23% from other races, and 0.35% from two or more races. 0.71% of the population were Hispanic or Latino of any race. 46.0% were of German, 12.5% Irish, 8.6% American, 7.5% English and 5.4% Czech ancestry. There were 4,608 households out of which 31.60% had children under the age of 18 living with them, 60.70% were married couplesliving together, 5.60% had a female householder with no husband present, and 31.20% were non-families. 28.70% of all households were made up of individuals and 15.10% had someone living alone who was 65 years of age or older. The average household size was 2.46 and the average family size was 3.06. The county population contained 27.30% under the age of 18, 5.70% from 18 to 24, 24.50% from 25 to 44, 22.70% from 45 to 64, and 19.80% who were 65 years of age or older. The median age was 40 years. For every 100 females there were 96.90 males. For every 100 females age 18 and over, there were 93.50 males. The median income for a household in the county was $30,738, and the median income for a family was $37,463. Males had a median income of $24,681 versus $17,593 for females. The per capita income for the county was $15,256. About 9.80% of families and 13.00% of the population were below the poverty line, including 15.00% of those under age 18 and 12.10% of those age 65 or over.
Holt County voters have historically tended to vote Republican. In only two elections since 1916 has the county selected the Democratic Party candidate.
