2000 census
As of the census [10] of 2000, there were 4,342 people, 1,770 households, and 1,196 families living in the county. The population density was 0.88 people per square mile (0.34 people/km2). There were 2,983 housing units at an average density of 0.60 units per square mile (0.23 units/km2). The racial makeup of the county was 97.28% White, 0.55% Native American, 0.02% Asian, 0.02% Pacific Islander, 1.17% from other races, and 0.94% from two or more races. 4.21% of the population were Hispanic or Latino of any race. 18.6% were of English, 17.0% German, 10.9% Irish and 9.9% American ancestry.
There were 1,770 households, out of which 29.90% had children under the age of 18 living with them, 60.10% were married couples living together, 4.40% had a female householder with no husband present, and 32.40% were non-families. 27.70% of all households were made up of individuals, and 11.30% had someone living alone who was 65 years of age or older. The average household size was 2.41 and the average family size was 2.96.
In the county, the population was distributed as follows: 25.50% were under 18, 4.80% were between 18 and 24, 25.90% were between 25 and 44, 29.30% were between 45 and 64, and 14.50% were 65 or older. The median age was 41 years. There were 104.50 males for every 100 females, and for every 100 females aged 18 and over, there were 106.80 males.
The median income for a household in the county was $32,174, and the median income for a family was $39,551. Males had a median income of $32,255 versus $21,463 for females. The per capita income for the county was $15,783. About 10.70% of families and 14.30% of the population were below the poverty line, including 16.70% of those under age 18 and 12.80% of those age 65 or over.
2010 census
As of the 2010 United States census, there were 4,368 people, 1,936 households, and 1,244 families living in the county. [11] The population density was 0.9 inhabitants per square mile (0.35/km2). There were 3,103 housing units at an average density of 0.6 units per square mile (0.23 units/km2). [12] The racial makeup of the county was 96.4% white, 0.6% American Indian, 0.2% black or African American, 0.2% Asian, 0.1% Pacific islander, 1.5% from other races, and 1.0% from two or more races. Those of Hispanic or Latino origin made up 4.0% of the population. [11] In terms of ancestry, 34.3% were English, 25.6% were German, 19.5% were Irish, and 2.8% were American. [13]
Of the 1,936 households, 24.2% had children under the age of 18 living with them, 55.7% were married couples living together, 4.8% had a female householder with no husband present, 35.7% were non-families, and 30.2% of all households were made up of individuals. The average household size was 2.25 and the average family size was 2.74. The median age was 48.0 years. [11]
The median income for a household in the county was $41,910 and the median income for a family was $56,710. Males had a median income of $42,865 versus $27,317 for females. The per capita income for the county was $22,625. About 10.1% of families and 13.8% of the population were below the poverty line, including 19.2% of those under age 18 and 13.2% of those age 65 or over. [14]
United States
Idaho 
