Canyon County is a county in Idaho, United States, on the west side of the Boise metropolitan area along the Snake River plain. It had a population of 231,105 at the 2020 census and covers 604 square miles (1,560 km2) centred near 43°38′N 116°43′W.
Caldwell is the county seat, and its postal code is 83605. The county holds 9 incorporated cities, plus a handful of unincorporated communities and rural crossroads. Canyon County sits in the Mountain time zone and carries FIPS code 16027.
Towns & Villages in Canyon County
Canyon County’s population is concentrated in Nampa and Caldwell, its two largest cities, with smaller incorporated towns along the Boise River and Snake River bottomlands and a long list of rural unincorporated crossroads that never grew into towns. CDP = census-designated place; Unincorp. = unincorporated community or locality with no formal municipal government.
| Place | Type | Pop. | ZIP |
|---|---|---|---|
| Caldwell | City · seat | 59,996 | 83605 |
| Nampa | City | 100,200 | 83651 |
| Middleton | City | 9,425 | 83644 |
| Parma | City | 2,096 | 83660 |
| Wilder | City | 1,597 | 83676 |
| Notus | City | 609 | 83656 |
| Greenleaf | City | 812 | 83626 |
| Melba | City | 572 | 83641 |
| Star | City (partial) | — | 83669 |
| Sunnyslope | Unincorp. | — | — |
| Huston | Unincorp. | — | 83630 |
| Bowmont | Unincorp. | — | — |
| Roswell | Unincorp. | — | — |
| Walters Ferry | Unincorp. | — | — |
| Apple Valley | Unincorp. | — | — |
| Central Cove | Unincorp. | — | — |
| Karcher Junction | Unincorp. | — | — |
| Kings Corner | Unincorp. | — | — |
| Knowlton Heights | Unincorp. | — | — |
| Swartz Corner | Unincorp. | — | — |
| Tiegs Corner | Unincorp. | — | — |
| Underkoflers Corner | Unincorp. | — | — |
| Weitz | Unincorp. | — | — |
| Westma | Unincorp. | — | — |
Star is a city split between Ada and Canyon counties, with the bulk of its population and its municipal offices on the Ada County side; only its western edge lies in Canyon County. Simplot, a name that appears on some older place lists, refers to the J.R. Simplot Company’s agribusiness operations near Caldwell rather than a distinct settlement, so it is not carried over here.
ZIP Codes
- 83605 — Caldwell
- 83651 — Nampa
- 83686 — Nampa (also serves Sunnyslope)
- 83687 — Nampa
- 83644 — Middleton
- 83660 — Parma
- 83676 — Wilder
- 83656 — Notus
- 83626 — Greenleaf
- 83641 — Melba
- 83630 — Huston (PO Box only)
- 83669 — Star
Small unincorporated crossroads such as Bowmont, Roswell, Walters Ferry and the rural “corner” communities have no ZIP code of their own and use the nearest city’s postal address.
Geography
Canyon County lies on the Snake River plain, a broad, flat basin irrigated by canals off the Boise and Snake rivers that turned the area into one of Idaho’s most productive farm belts. The Boise River crosses the county’s northeast corner past Middleton and Star, and the Snake River forms the county’s southern and western boundary with Owyhee County and Malheur County, Oregon. Elevations across the county stay close to 2,300–2,400 feet, with little relief outside the river canyons.
Canyon County borders Payette County to the north, Gem County to the northeast, Ada County to the east, Owyhee County to the south, and Malheur County, Oregon, to the west.
Demographics
Canyon County had 231,105 residents at the 2020 census, making it Idaho’s second-most-populous county after Ada County. Nampa, the largest city, and Caldwell, the county seat, together hold roughly two-thirds of the county’s population. The county’s median household income runs below the Idaho median of $74,942, reflecting its large agricultural workforce; population density is about 383 people per square mile, well above the statewide average. Canyon County has one of Idaho’s largest Hispanic and Latino communities, a legacy of decades of migrant farm labor in the Treasure Valley’s orchards and row-crop fields.
Economy & Local Life
Agriculture and food processing anchor the county’s economy: J.R. Simplot Company, Church Brothers, and a cluster of dairy, potato, hop and mint operations around Caldwell, Parma, and Wilder still supply national food and beverage brands. Nampa has diversified into manufacturing, retail, and healthcare, anchored by St. Luke’s and Saint Alphonsus hospital campuses and the College of Western Idaho’s main Nampa campus. The Nampa Civic Center hosts the Western Idaho Fair, one of the state’s largest annual fairs, each August.
History
The Idaho territorial legislature created Canyon County out of Ada County by an act approved March 7, 1891, with the split taking effect after the November 1892 election. The name comes from the canyon of the Boise River near the county’s original boundary. The Oregon Short Line Railroad, extended through Nampa and Caldwell in the 1880s, drove the county’s early settlement, and large-scale federal and private irrigation projects in the early 1900s converted its sagebrush desert into farmland.
Getting There
Interstate 84 crosses the county through Nampa and Caldwell, and U.S. Route 20/26 links Caldwell to Parma and Notus.
- Boise — 20 miles east
- Meridian — 12 miles east
- Ontario, Oregon — 25 miles west
- Mountain Home — 45 miles southeast
Boise Airport (BOI), Idaho’s largest commercial airport, is the nearest air service, about 20 miles from Caldwell.
Frequently Asked Questions
Where is Canyon County, Idaho?
It sits in southwestern Idaho on the Snake River plain, immediately west of Ada County and the city of Boise, forming the western half of the Boise metropolitan area.
What is the population of Canyon County?
231,105 at the 2020 census, Idaho’s second-highest county total.
How big is Canyon County?
604 square miles (1,560 km2), including about 16 square miles of water along the Snake and Boise rivers.
What is the county seat of Canyon County?
Caldwell is the county seat.
How many towns and cities are in Canyon County?
Nine incorporated cities — Caldwell, Nampa, Middleton, Parma, Wilder, Notus, Greenleaf, Melba and a small part of Star — plus several unincorporated communities.
What ZIP codes are in Canyon County?
Standard ZIP codes include 83605 (Caldwell), 83651/83686/83687 (Nampa), 83644 (Middleton), 83660 (Parma), 83676 (Wilder), 83656 (Notus), 83626 (Greenleaf) and 83641 (Melba).
What is Canyon County known for?
Its irrigated farmland — potatoes, hops, mint, and dairy — and the J.R. Simplot Company’s agribusiness operations based near Caldwell.
More counties in this state: Towns and villages in Idaho.