Twin Falls County, Idaho

Twin Falls County is a county in Idaho, United States, about 130 miles southeast of Boise in the
Magic Valley region. It had a population of 90,046 at the 2020 census, an estimated 93,734 by
2024, and covers 1,921 square miles (4,980 km2) centred near 42°21′N 114°40′W.

Twin Falls is the county seat and the county’s largest city; its postal code is 83301. The
county holds 8 cities and 12 unincorporated communities, and it runs on Mountain Time. Its FIPS
code is 16083.

Towns & Villages in Twin Falls County

Twin Falls County has 20 named places on record: all 8 are incorporated cities, and 12 are
unincorporated communities with no local government of their own. Unincorp. covers crossroads and
rural settlements with no formal boundary; several are historic stage-stop or railroad-siding
names that no longer have year-round residents.

Hollister has no post office of its own; its mail is delivered under Twin Falls’s 83301
code even though the town sits roughly 30 miles south of the city, near the Nevada line. Milner
Dam, on the Snake River at the county’s northeast corner, is a shared landmark rather than a
settlement — it extends into both Jerome and Cassia Counties and has no population of its
own.

Geography

Twin Falls County sits on the Snake River Plain in south-central Idaho, a broad, flat expanse
of volcanic soil cut sharply by the Snake River Canyon. Of its 1,921 square miles, 1,914 are land
and 7.1 are water, a small share reflecting the county’s high desert setting away from the
canyon rim. The Snake River forms most of the county’s northern boundary, running through a
canyon several hundred feet deep; Rock Creek and Salmon Falls Creek are the other principal
waterways, both feeding irrigation for the county’s farmland.

Gooding County lies to the north, Jerome County to the northeast, Cassia County to the east,
Elko County, Nevada to the south, Owyhee County to the west, and Elmore County to the northwest.
Gooding County, Jerome County, Cassia County, Owyhee County and Elmore County all border Twin Falls
directly; Elko County, across the state line in Nevada, has no page on this site.

Demographics

Twin Falls County had a population of 90,046 at the 2020 census, and the latest estimate puts
the county near 93,734 residents in 2024. Twin Falls and Kimberly are by far the two largest
communities, together holding well over half the county’s population. Median household
income runs $67,409 (2023 ACS), below Idaho’s statewide figure of $74,942 (2023 ACS).
Population density works out to roughly 47 people per square mile of land, low even by Idaho
standards outside the county’s Twin Falls-Kimberly core.

Economy & Local Life

Health care and social assistance employs the most workers in the county, about 6,111 people,
followed by retail trade at 5,884 and manufacturing at 5,868. Chobani operates the world’s
largest yogurt manufacturing plant in Twin Falls, opened in 2012, alongside Glanbia Foods
(cheese) and Amalgamated Sugar Company, both major food-processing employers in the city.
Lamb Weston runs a potato-processing plant in the county as well. Buhl, on the county’s
western edge, calls itself the Trout Capital of the World; Clear Springs Foods, the world’s
largest rainbow trout producer, processes over 20 million pounds of trout there each year. The
Twin Falls County Fair, held in Filer since 1916, runs each year in the first week of
September and is the county’s biggest annual event.

History

Twin Falls County was organized on 21 February 1907, carved out of Cassia County after the
city of Twin Falls was founded in 1904 and the Milner Dam irrigation project was completed in
1905. The county takes its name from a split waterfall on the Snake River, near the site of the
present-day city. The dam and the canal system it fed turned the surrounding sagebrush desert
into irrigated farmland almost overnight, drawing the settlers who founded Twin Falls, Buhl,
Filer and Kimberly within a few years of one another.

Getting There

No interstate highway crosses Twin Falls County. US Route 30 and US Route 93 are the main
through routes, along with Idaho State Highways 50 and 74; US 93 crosses the Snake River on the
Perrine Bridge just north of Twin Falls, one of the few sites in the country where BASE jumping
is legally permitted year-round.

• Boise — about 130 miles northwest
• Pocatello — about 110 miles northeast
• Sun Valley/Ketchum — about 90 miles north
• Jackpot, Nevada — about 50 miles south

Joslin Field–Magic Valley Regional Airport, on Twin Falls’s south side, is the
county’s commercial airport, with Delta Connection service to Salt Lake City. Idaho has no
active Amtrak passenger rail service; the nearest stations are out of state.

Frequently Asked Questions

Where is Twin Falls County located?
It sits on the Snake River Plain in south-central Idaho, about 130 miles southeast of Boise,
bordered by Gooding, Jerome, Cassia, Owyhee and Elmore Counties and Elko County, Nevada.

What is the population of Twin Falls County?
90,046 at the 2020 census, with a 2024 estimate near 93,734.

How big is Twin Falls County?
1,921 square miles (4,980 km2), of which 1,914 square miles are land.

What is the county seat of Twin Falls County?
Twin Falls, organized as the county seat when the county formed in 1907, is also the largest
city.

How many towns and cities are in Twin Falls County?
Eight incorporated cities — Twin Falls, Kimberly, Buhl, Filer, Hansen, Hollister,
Castleford and Murtaugh — plus a dozen unincorporated communities including Rogerson,
Rock Creek and Artesian City.

What ZIP codes does Twin Falls County use?
83301 to 83303 for Twin Falls and Hollister; 83341 for Kimberly, 83316 for Buhl, 83328 for
Filer, 83334 for Hansen, 83321 for Castleford and 83344 for Murtaugh.

What is Twin Falls County known for?
The Perrine Bridge over the Snake River Canyon, a legal year-round BASE jumping site, and
Chobani’s Twin Falls plant, the world’s largest yogurt manufacturing facility.

More counties in this state: Towns and villages in Idaho.