Cloud County's population was estimated to be 9,594 in the year 2006, a decrease of 627, or -6.1%, over the previous six years.
As of the U.S. Census in 2000, there were 10,268 people, 4,163 households, and 2,697 families residing in the county. The population density was 14 people per square mile (6/km²). There were 4,838 housing units at an average density of 7 per square mile (3/km²). The racial makeup of the county was 98.30% White, 0.34% Black or African American, 0.25% Native American, 0.25% Asian, 0.13% from other races, and 0.73% from two or more races. Hispanic or Latino of any race were 0.60% of the population.
There were 4,163 households out of which 27.10% had children under the age of 18 living with them, 55.10% were married couples living together, 6.60% had a female householder with no husband present, and 35.20% were non-families. 30.80% of all households were made up of individuals and 15.90% had someone living alone who was 65 years of age or older. The average household size was 2.31 and the average family size was 2.89.
In the county the population was spread out with 22.40% under the age of 18, 10.40% from 18 to 24, 21.90% from 25 to 44, 22.20% from 45 to 64, and 23.20% who were 65 years of age or older. The median age was 41 years. For every 100 females there were 90.60 males. For every 100 females age 18 and over, there were 86.60 males.
The median income for a household in the county was $31,758, and the median income for a family was $39,745. Males had a median income of $27,166 versus $20,114 for females. The per capita income for the county was $17,536. About 6.40% of families and 10.80% of the population were below the poverty line, including 12.10% of those under age 18 and 8.70% of those age 65 or over.