Lewis and Clark County, Montana Demographics
Population trends, housing costs, income, commuting, and health, all on one page.
Lewis and Clark County, MT Population Density Map and Area Scores
Area Score
Health, income and education, each graded from F to A+. Explore interactive maps for deeper analysis.
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B
Health Around averageAmong the top 5 healthiest counties in Montana
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B
Income Around averageAmong the top 5 wealthiest counties in Montana
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B
Education Around averageAmong the top 3 best educated counties in Montana
Source: Map AI Methodology
Population: density and quick facts
| Metric | Lewis and Clark County | Montana Avg | U.S. Average |
|---|---|---|---|
| Population | 73,430 | 1,116,812 | 337,468,954 |
| Population density (per sq mi) | 21.0 | 7.6 | 86.4 |
| Population growth (%/yr) | 1.34% | 1.09% | 0.59% |
| Median age | 42.9 | 40.7 | 37.3 |
| Households | 31,201 | 458,835 | 130,235,071 |
Population in Lewis and Clark County grew by 22.4% from 2009 to 2024, reaching 73,430 in 2024.
Population Growth 2009–2024
Race & Ethnicity
Age & Sex
The largest generation in Lewis and Clark County is Gen X, aged 45–60, at 21.2% of residents. That is 1.7 points above Montana as a whole.
- Gen Z 13–28 14,287 19.5% -2.0 pts
- Millennials 29–44 15,298 20.8% +0.4 pts
- Gen X 45–60 15,532 21.2% +1.7 pts
- Boomers 61–79 14,245 19.4% on par
Residents by birth cohort, from the 2025 age distribution. The right-hand figure is how far each cohort's share sits above or below Montana, in percentage points. Children younger than Gen Z and the generations before the Boomers are counted in the population but not shown here, so these shares do not add up to 100%.
Male and female share
Women are 50.3% of the people living in Lewis and Clark County and men 49.7%.
- Women 50.3% Montana 49.4%
- Men 49.7% Montana 50.6%
How many residents match a customer profile?
Residents matching this profile
100% of everyone living in Lewis and Clark County
Pick an age range and a women/men split and the figure above answers with how many residents that profile reaches.
Economy
Lewis and Clark County has a the economy index of B, which means it is quite prosperous.
| Metric | Lewis and Clark County | Montana Avg | U.S. Average |
|---|---|---|---|
| Median household income | $79,279 | $72,476 | $80,455 |
| Income growth (%/yr) | 3.68% | 5.17% | 4.80% |
| Unemployment rate | 3.2% | 3.6% | 5.2% |
The median household income in Lewis and Clark County is about 9% higher than in Montana.
Housing
| Metric | Lewis and Clark County | Montana Avg | U.S. Average |
|---|---|---|---|
| Median home price | $310,934 | $249,140 | $248,835 |
| Median rent | $1,101 | $1,081 | $1,407 |
| Homeownership rate | 70.1% | 69.2% | 65.2% |
The median home price in Lewis and Clark County is about 23.5 years' worth of rent — buying at the median price costs roughly as much as paying the median rent of $1,101 per month for that long.
Commute Time & Mobility
Commuters in Lewis and Clark County spend about 32 minutes on the road round trip each working day. Over a typical 250-day work year, that adds up to roughly 135 hours, about 5.6 full days, spent commuting.
| Metric | Lewis and Clark County | Montana Avg | U.S. Average |
|---|---|---|---|
| One-way commute (min) | 16.2 | 16.0 | 22.4 |
| Round-trip commute (min) | 32.4 | 32.1 | 44.8 |
| Yearly time spent (hours) | 135 | 134 | 187 |
| Estimated yearly cost | $4,191 | $4,143 | $5,790 |
| Work from home | 14.5% | 12.5% | 15.0% |
| Highway traffic (vehicles/day) | 1,675 | 2,162 | 8,813 |
| Local road traffic (vehicles/day) | 903 | 403 | 1,355 |
Fastest commutes among counties in
Montana:
Treasure County (7.2 min), Rosebud County (8.2 min), Fallon County (8.4 min).
Slowest:
Broadwater County (30.3 min), Stillwater County (27.8 min), Granite County (23.3 min).
The average commute time in Lewis and Clark County is about the same as in Montana.
Estimated yearly cost applies a single national wage rule of thumb (U.S. Bureau of Labor Statistics average hourly earnings), not a measurement of wages in this area. Traffic volume figures come from proprietary Ticon and TrafficZoom data.
Education & Households
Lewis and Clark County has a education index of B, which means it is quite educated.
| Metric | Lewis and Clark County | Montana Avg | U.S. Average |
|---|---|---|---|
| Bachelor's degree or higher | 40.3% | 31.3% | 31.6% |
| Average household size | 2.30 | 2.37 | 2.53 |
Highest education index among counties in
Montana:
Gallatin County (0.4), Missoula County (0.3), Lewis and Clark County (0.3).
Lowest:
Liberty County (0.2), Toole County (0.2), Wheatland County (0.2).
Health
Lewis and Clark County has a health index of B, which means it is quite healthy.
| Metric | Lewis and Clark County | Montana Avg | U.S. Average |
|---|---|---|---|
| Life expectancy (years) | 79.3 | 79.0 | 78.3 |
| Self-rated poor health | 11.6% | 14.7% | 16.3% |
| Smokers | 15.2% | 18.8% | 19.0% |
Highest health index among counties in
Montana:
Gallatin County (0.8), Missoula County (0.8), Granite County (0.8).
Lowest:
Glacier County (0.7), Big Horn County (0.8), Roosevelt County (0.8).
Lewis and Clark County, MT Compared With Nearby Counties
How Lewis and Clark County, MT compares with the 1 counties closest to it.
| Area | Population | Median household income | Median home price | Commute |
|---|---|---|---|---|
| Lewis and Clark County, MT | 73,430 | $79,279 #1/2 | $310,934 #1/2 | 16.2 min #2/2 |
| Cascade County, MT | 84,603 | $67,044 | $239,166 | 13.9 min |
Frequently Asked Questions
Common questions about Lewis and Clark County, Montana.
How big is Lewis and Clark County, Montana by population?
About 73,430 people live in Lewis and Clark County, Montana, in 31,201 households of 2.3 people on average. The median age is 42.9, so residents are older than the U.S. median of 37.3 by about 6 years.
Is Lewis and Clark County, Montana mostly urban or rural?
Averaged over its land area, Lewis and Clark County, Montana has 21 people per square mile, a density typical of rural areas. That is about 24% of the U.S. average of 86.
How affordable is housing in Lewis and Clark County, Montana?
The median home costs 3.9 times the median household income ($310,934 against $79,279), compared with 3.1 times nationally. A ratio of about 3 is traditionally considered affordable. Median rent of $1,101 a month takes about 17% of the median household's income, below the 30% level at which HUD considers renters cost-burdened.
Is it hard to find a job in Lewis and Clark County, Montana?
Unemployment in Lewis and Clark County, Montana is only 3.2%, well below the U.S. rate of 5.2%, a sign of a tight labor market where employers compete for workers.
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