Minidoka County is a county in Idaho, United States, part of the Magic Valley region south of the Snake River. It had a population of 21,613 at the 2020 census and covers 763 square miles (1,980 km2) centred near 42°51′N 113°38′W.
Rupert is the county seat, and its postal code is 83350. The county has five incorporated cities and several unincorporated communities, sits in the Mountain time zone, and carries FIPS code 16067. It forms part of the Burley, Idaho micropolitan statistical area.
Towns & Villages in Minidoka County
Minidoka County has five incorporated cities — Rupert, Heyburn, Paul, Acequia and Minidoka — plus a small share of Burley, which straddles the Cassia County line, and a handful of unincorporated places. CDP = census-designated place; Unincorp. = unincorporated community with no formal city government.
| Place | Type | Pop. | ZIP |
|---|---|---|---|
| Rupert | City · seat | 6,246 | 83350 |
| Heyburn | City | 3,461 | 83336 |
| Paul | City | 1,090 | 83347 |
| Burley (part) | City | — | — |
| Acequia | City | — | — |
| Minidoka | Unincorp. | — | 83343 |
| Jackson | Unincorp. | — | — |
| Kimama | Unincorp. | — | — |
| Myers | Unincorp. | — | — |
| Norland | Unincorp. | — | — |
Most of Burley, the county’s largest urban center, actually lies across the line in neighboring Cassia County; only its northern edge extends into Minidoka County, so Burley itself is profiled on the Cassia County page.
ZIP Codes
- 83350 — Rupert (also serves nearby rural addresses)
- 83336 — Heyburn
- 83347 — Paul
- 83343 — Minidoka (post-office-box service)
Acequia and the county’s smaller unincorporated communities are served by the Rupert or Paul post offices rather than a ZIP of their own.
Geography
Minidoka County sits in the Snake River Plain, an irrigated farming basin fed by the Snake River, which forms part of the county’s northern edge, and by the federal Minidoka Project canal system. The southern part of the county rises onto sagebrush rangeland toward the Cassia County line. The county borders Blaine County to the north and east, Cassia County to the south, Jerome County to the west, and Lincoln County to the northwest.
Demographics
The 2020 census counted 21,613 residents. Rupert and Heyburn are the two largest communities, together holding roughly half the county’s population. Minidoka County’s median household income runs well below the Idaho median of $74,942, reflecting the county’s agriculture-dependent economy. Population density is about 28 people per square mile.
Economy & Local Life
Agriculture drives the county’s economy — potatoes, sugar beets, dry beans, and dairy operations dominate the irrigated Snake River Plain farmland, supported by food-processing plants in and around Rupert and Heyburn. The Minidoka County Fair, held each August in Rupert, is the county’s largest annual event.
History
Minidoka County was created on January 28, 1913, from part of Lincoln County. Its name comes from a Dakota Sioux word meaning “a fountain or spring of water.” The federal Minidoka Project, launched under Theodore Roosevelt’s administration in 1904–1906, dammed and canalled the Snake River to irrigate the county’s farmland and remains central to its economy today. During World War II, the Minidoka War Relocation Center, one of ten camps that incarcerated Japanese Americans, operated just outside the county in neighboring Jerome County despite carrying the Minidoka name; the site is preserved today as Minidoka National Historic Site.
Getting There
Interstate 84 crosses the county through Rupert and Heyburn, linking it to Twin Falls to the west and Pocatello to the east.
- Twin Falls — 30 miles west
- Pocatello — 65 miles east
- Boise — 140 miles northwest
- Sun Valley — 75 miles northeast
The nearest commercial airport is Magic Valley Regional Airport in Twin Falls.
Frequently Asked Questions
Where is Minidoka County, Idaho?
It lies in south-central Idaho, along the Snake River in the Magic Valley region, between Twin Falls and Pocatello.
What is the population of Minidoka County?
21,613 residents at the 2020 census.
How big is Minidoka County?
763 square miles (1,980 km2), of which 758 square miles is land.
What is the county seat of Minidoka County?
Rupert is the county seat.
How many towns are in Minidoka County?
Five incorporated cities — Rupert, Heyburn, Paul, Acequia and Minidoka — plus part of Burley and several unincorporated communities.
What ZIP codes are in Minidoka County?
83350 (Rupert), 83336 (Heyburn), 83347 (Paul) and 83343 (Minidoka).
Why is Minidoka County named that?
The name comes from a Dakota Sioux word for a spring or fountain of water, chosen for the federal irrigation project that shaped the county.
More counties in this state: Towns and villages in Idaho.