In the Nebraska license plate system, Valley County is represented by the prefix 47 (it had the forty-seventh-largest number of vehicles registered in the county when the license plate system was established in 1922).
1880 - 2,324 1890 - 7,092 1900 - 7,339 1910 - 9,480 1920 - 9,823 1930 - 9,533 1940 - 8,163 1950 - 7,252 1960 - 6,590 1970 - 5,783 1980 - 5,633 1990 - 5,169 2000 - 4,647
As of the census of 2000, there were 4,647 people, 1,965 households, and 1,298 families residing in the county. The population density was 8 people per square mile (3/km²). There were 2,273 housing units at an average density of 4 per square mile (2/km²). The racial makeup of the county was 98.15% White, 0.15% Black or African American, 0.32% Native American, 0.11% Asian, 0.06% Pacific Islander, 0.80% from other races, and 0.41% from two or more races. 1.61% of the population were Hispanic or Latino of any race.
There were 1,965 households out of which 28.00% had children under the age of 18 living with them, 58.70% were married couples living together, 5.10% had a female householder with no husband present, and 33.90% were non-families. 31.00% of all households were made up of individuals and 17.90% had someone living alone who was 65 years of age or older. The average household size was 2.32 and the average family size was 2.93.
In the county the population was spread out with 24.70% under the age of 18, 4.80% from 18 to 24, 22.60% from 25 to 44, 23.90% from 45 to 64, and 24.00% who were 65 years of age or older. The median age was 44 years. For every 100 females there were 91.70 males. For every 100 females age 18 and over, there were 90.50 males.
The median income for a household in the county was $27,926, and the median income for a family was $35,571. Males had a median income of $25,224 versus $17,217 for females. The per capita income for the county was $14,996. About 10.10% of families and 12.80% of the population were below the poverty line, including 16.30% of those under age 18 and 12.70% of those age 65 or over.