Lewis and Clark County is a county in Montana, United States, home to the state capital, Helena. It had a population of 70,973 at the 2020 census and covers 3,498 square miles (9,060 km2) — 3,459 square miles (8,960 km2) of land and 39 square miles (100 km2) of water — centred near 47°07′N 112°23′W.
Helena is the county seat, and its postal code is 59601. The county holds 2 incorporated cities, several census-designated places around the Helena Valley and Canyon Ferry Lake, and a scatter of unincorporated communities; Montana does not use civil townships. The county sits in the Mountain time zone and carries FIPS code 30049.
Towns & Villages in Lewis and Clark County
Lewis and Clark County has 2 incorporated cities — Helena, the seat, and East Helena — plus 6 census-designated places (CDPs) clustered around the Helena Valley and Canyon Ferry Lake, and a dozen or so unincorporated communities scattered through the mountains and river valleys to the north and west. CDP figures are the Census Bureau’s 2020 counts for those specific places, not the whole county.
| Place | Type | Pop. | ZIP |
|---|---|---|---|
| Helena | City · seat | 32,091 | 59601 |
| East Helena | City | 1,944 | 59635 |
| Helena Valley Northeast | CDP | — | 59602 |
| Helena Valley Northwest | CDP | — | 59602 |
| Helena Valley Southeast | CDP | — | 59601 |
| Helena Valley West Central | CDP | — | 59601 |
| Helena West Side | CDP | — | 59601 |
| Lakeside | CDP | — | 59602 |
| Lincoln | Unincorp. | — | 59639 |
| Wolf Creek | Unincorp. | — | 59648 |
| Craig | Unincorp. | — | 59648 |
| Marysville | Unincorp. | — | — |
| Rimini | Unincorp. | — | — |
| Canyon Creek | Unincorp. | — | — |
| Canyon Ferry | Unincorp. | — | — |
| Silver City | Unincorp. | — | — |
| York | Unincorp. | — | — |
| Winston | Unincorp. | — | — |
| Austin | Unincorp. | — | — |
| Dearborn | Unincorp. | — | — |
| Frontier Town | Unincorp. | — | — |
| Wilborn | Unincorp. | — | — |
Fort William Henry Harrison, a Montana National Guard installation just west of Helena, is a separate populated place from the city proper and is sometimes listed alongside it. A number of names carried on older place lists for this county — several labelled “Trailer Court” or “MH Park,” plus scattered private-subdivision names — are mobile-home parks or platted subdivisions rather than recognised populated places, and are omitted here; see notes.
ZIP Codes
- 59601 — Helena (also serves Helena Valley Southeast, Helena Valley West Central and Helena West Side)
- 59602 — Helena (also serves Helena Valley Northeast, Helena Valley Northwest and Lakeside)
- 59635 — East Helena
- 59639 — Lincoln
- 59648 — Wolf Creek (also serves Craig)
Smaller unincorporated communities such as Marysville, Rimini, Canyon Creek and York use Helena or Wolf Creek postal addresses rather than their own ZIP codes.
Geography
Lewis and Clark County straddles the Continental Divide in west-central Montana, running from the Big Belt and Elkhorn mountains in the east across the broad Helena Valley to the Rocky Mountain Front and Scapegoat Wilderness in the west. The Missouri River enters the county at Canyon Ferry Lake, a reservoir behind Canyon Ferry Dam southeast of Helena, and flows north through the county past Helena, Wolf Creek and Craig before turning toward Great Falls. The Dearborn and Blackfoot river systems drain the county’s western reaches.
Lewis and Clark County borders Teton County to the north; Cascade County and Meagher County to the east; Broadwater County to the southeast; Jefferson County to the south; Powell County to the west; and Flathead County to the northwest.
Demographics
Lewis and Clark County had 70,973 residents at the 2020 census. Helena, the county seat and state capital, is by far the largest community at 32,091, followed by East Helena at 1,944; most of the county’s remaining population lives in the unincorporated Helena Valley CDPs that ring the capital. The county’s median household income runs above the Montana median of $70,804, reflecting the concentration of state-government and professional jobs in Helena. Population density is roughly 20 people per square mile of land, though most residents live within a few miles of Helena.
Economy & Local Life
Montana’s state government is the county’s dominant employer — Helena is the seat of Montana’s government, and roughly a fifth of the city’s workforce works for state agencies. Carroll College and Helena College University of Montana anchor higher education, while Fort William Henry Harrison houses Montana National Guard training and the Fort Harrison VA Medical Center. Outside Helena, ranching, forestry and recreation tied to Canyon Ferry Lake and the Blackfoot and Missouri river fisheries support the smaller communities.
History
Lewis and Clark County was created on June 2, 1865, as one of nine original counties of Montana Territory. It was first named Edgerton County, for Sidney Edgerton, the territory’s first governor, then renamed Lewis and Clark County on March 1, 1868, honoring explorers Meriwether Lewis and William Clark, whose 1805 expedition passed through the Missouri River valley here. Gold strikes at Last Chance Gulch in 1864 founded Helena, and later silver mining built boomtowns such as Marysville and Rimini — both now largely ghost towns — before Helena’s selection as territorial, then state, capital cemented its role as the county’s anchor.
Getting There
Interstate 15 runs north–south through the county via Helena and Wolf Creek, meeting US Highway 12 (east–west) in Helena and US Highway 287 running southeast toward Townsend. Montana Highway 200 crosses the county’s northwest toward Lincoln and the Blackfoot valley.
- Great Falls — 90 miles northeast
- Butte — 65 miles south
- Missoula — 115 miles west
- Bozeman — 100 miles southeast
Helena Regional Airport, inside the city, offers the county’s only commercial air service.
Frequently Asked Questions
Where is Lewis and Clark County, Montana?
It lies in west-central Montana, straddling the Continental Divide, with Helena, the state capital, at its center.
What is the population of Lewis and Clark County?
70,973 residents at the 2020 census.
How big is Lewis and Clark County?
3,498 square miles (9,060 km2), of which 39 square miles is water, chiefly Canyon Ferry Lake.
What is the county seat of Lewis and Clark County?
Helena, which is also Montana’s state capital.
How many towns are in Lewis and Clark County?
Two incorporated cities — Helena and East Helena — plus six census-designated places and about a dozen unincorporated communities.
What ZIP codes are in Lewis and Clark County?
Mainly 59601 and 59602 (Helena and the Helena Valley), 59635 (East Helena), 59639 (Lincoln) and 59648 (Wolf Creek and Craig).
Why is the county named Lewis and Clark?
It honors explorers Meriwether Lewis and William Clark, whose 1805 Missouri River expedition passed through the area; the county was originally named Edgerton County after Montana’s first territorial governor before being renamed in 1868.
More counties in this state: Towns and villages in Montana.