Minidoka County was created by the Idaho Legislature on January 28, 1913 by a partition of Lincoln County. The name Minidoka is of Dakota Sioux origin meaning "a fountain or spring of water." [2] Minidoka was first used in 1883 as a name for a Union Pacific, Oregon Short Line, spur in the middle of the Snake River Plain. The spur later became the site of a watering station along the line. The village of Minidoka grew up next to the station. Minidoka was then given to a reclamation project under then President Theodore Roosevelt. The Minidoka Dam and Minidoka National Historic Site (not in Minidoka County) share the name.
Minidoka County is part of the Burley, Idaho Micropolitan Statistical Area.
As of the census of 2000, there were 20,174 people, 6,973 households, and 5,362 families residing in the county. The population density was 27 people per square mile (10/km²). There were 7,498 housing units at an average density of 10 per square mile (4/km²). The racial makeup of the county was 78.07% White, 0.26% Black or African American, 0.88% Native American, 0.42% Asian, 0.02% Pacific Islander, 17.83% from other races, and 2.52% from two or more races. 25.46% of the population were Hispanic or Latino of any race. 18.1% were of English, 12.9% German and 12.0% American ancestry according to Census 2000.
There were 6,973 households out of which 38.90% had children under the age of 18 living with them, 64.40% were married couples living together, 8.20% had a female householder with no husband present, and 23.10% were non-families. 20.00% of all households were made up of individuals and 9.60% had someone living alone who was 65 years of age or older. The average household size was 2.87 and the average family size was 3.32.
In the county the population was spread out with 31.60% under the age of 18, 9.10% from 18 to 24, 25.20% from 25 to 44, 20.90% from 45 to 64, and 13.20% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 99.90 males. For every 100 females age 18 and over, there were 97.80 males.
The median income for a household in the county was $32,021, and the median income for a family was $36,500. Males had a median income of $28,977 versus $19,521 for females. The per capita income for the county was $13,813. About 11.90% of families and 14.80% of the population were below the poverty line, including 18.90% of those under age 18 and 9.00% of those age 65 or over.