2 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Helena | 1 | 35,966 | 32,255 | 1.75% | 2,085 | 17 | City |
| East Helena | 2 | 2,384 | 1,948 | 3.16% | 588 | 4 | City |
Helena is the largest city in Lewis and Clark County, with a population of 35,966.
East Helena is the smallest city in Lewis and Clark County, with a population of 2,384.
There are 2 cities in Lewis and Clark County, Montana.