Adjacent counties

• Gooding County - north
• Jerome County - northeast
• Cassia County - east
• Elko County, Nevada - south/Pacific Time Border
• Owyhee County - west
• Elmore County - northwest

Major highways

• US 30
• US 93
• SH-50
• SH-74

National protected areas

• Hagerman Fossil Beds National Monument
• Sawtooth National Forest (part)

2010 census

As of the 2010 census, there were 77,230 people, 28,760 households, and 19,954 families living in the county.^[11] The population density was 40.2 inhabitants per square mile (15.5/km²). There were 31,072 housing units at an average density of 16.2 per square mile (6.3/km²).^[12] The racial makeup of the county was 88.9% white, 1.2% Asian, 0.8% American Indian, 0.4% black or African American, 0.1% Pacific islander, 6.3% from other races, and 2.3% from two or more races. Those of Hispanic or Latino origin made up 13.7% of the population.^[11] In terms of ancestry, 20.2% were German, 14.5% were English, 10.8% were Irish, and 7.0% were American.^[13]

Of the 28,760 households, 35.4% had children under the age of 18 living with them, 54.1% were married couples living together, 10.5% had a female householder with no husband present, 30.6% were non-families, and 24.3% of all households were made up of individuals. The average household size was 2.65 and the average family size was 3.16. The median age was 34.4 years.^[11]

The median income for a household in the county was $42,455 and the median income for a family was $49,188. Males had a median income of $35,777 versus $26,257 for females. The per capita income for the county was $19,892. About 10.6% of families and 13.0% of the population were below the poverty line, including 16.9% of those under age 18 and 10.7% of those age 65 or over.^[14]

2000 census

As of the 2000 census, there were 64,284 people, 23,853 households, and 16,959 families living in the county. The population density was 33 inhabitants per square mile (13/km²). There were 25,595 housing units at an average density of 13 per square mile (5.0/km²). The racial makeup of the county was 92.47% White, 0.19% Black or African American, 0.71% Native American, 0.76% Asian, 0.08% Pacific Islander, 3.77% from other races, and 2.02% from two or more races. 9.37% of the population were Hispanic or Latino of any race. 17.9% were of German, 17.7% English, 10.9% American and 7.3% Irish ancestry.

There were 23,853 households, out of which 34.70% had children under the age of 18 living with them, 58.00% were married couples living together, 9.20% had a female householder with no husband present, and 28.90% were non-families. 23.60% of all households were made up of individuals, and 10.40% had someone living alone who was 65 years of age or older. The average household size was 2.64 and the average family size was 3.13.

In the county, the population was spread out, with 27.90% under the age of 18, 10.40% from 18 to 24, 26.00% from 25 to 44, 21.50% from 45 to 64, and 14.30% who were 65 years of age or older. The median age was 35 years. For every 100 females, there were 96.50 males. For every 100 females age 18 and over, there were 93.70 males.

The median income for a household in the county was $34,506, and the median income for a family was $39,886. Males had a median income of $30,058 versus $20,825 for females. The per capita income for the county was $16,678. About 9.10% of families and 12.70% of the population were below the poverty line, including 16.00% of those under age 18 and 9.30% of those age 65 or over.