Bordering states
Montana vs South Dakota
Short answer
- MT
- 1,137,233
- SD
- 924,669
The two states, county by county
Both maps share one density scale, so the same shade means the same number of people per square mile on either side of the border. Darker counties are denser. Select a county to open its page.
Montana
South Dakota
- < 1
- < 3
- < 5
- < 13
- ≥ 13
Residents, 2024
- 01Montana1,137,233
- 02South Dakota924,669
Land, square miles
- 01Montana145,550
- 02South Dakota75,808
People per square mile
- 01Montana7.8
- 02South Dakota12.2
Median county household income
- 01Montana$59,534
- 02South Dakota$67,180
Side by side
| Measure | Montana | South Dakota |
|---|---|---|
| Residents, 2024 | 1,137,233 | 924,669 |
| Rank by population | 43rd | 46th |
| Land, sq mi | 145,550 | 75,808 |
| People per sq mi | 7.8 | 12.2 |
| County-equivalents | 56 | 66 |
| Median county residents | 7,814 | 5,296 |
| Median county income | $59,534 | $67,180 |
| Most populous county | Yellowstone County | Minnehaha County |
| Largest county by land | Beaverhead County | Meade County |
| Capital | Helena | Pierre |
| Daylight at capital, June 21 | 15 h 50 min | 15 h 32 min |
| Census division | Mountain | West North Central |
Population and density
Montana has 1,137,233 residents, 23% more than South Dakota's 924,669. Montana ranks 43rd and South Dakota 46th of the 50 states and DC. South Dakota is the more crowded, with 12.2 people per square mile against 7.8, 56% more.
Land area
Montana has 145,550 square miles of land, 92% more than South Dakota's 75,808. The largest county-equivalent in Montana is Beaverhead County at 5,543 square miles; in South Dakota it is Meade County at 3,471.
Counties
South Dakota is divided into 66 county-equivalents and Montana into 56, so an average South Dakota county covers 1,149 square miles against 2,599. The typical county in Montana has 7,814 residents, against 5,296 in South Dakota. The most populous are Yellowstone County (171,583) and Minnehaha County (208,639).
3 county names appear on both sides of the border: Custer, Lake, Lincoln. Use the FIPS code, not the name, when joining data across the two states.
Household income
The median county in South Dakota has a household income of $67,180, 13% above Montana's $59,534. The highest county incomes are Gallatin County ($90,942) in Montana and Lincoln County ($102,130) in South Dakota, from SAIPE 2023.
Capitals and daylight
Helena and Pierre are 585 miles apart in a straight line; from Helena the initial bearing is 101°, E. On June 21, 2026, Helena gets 15 h 50 min of daylight and Pierre 15 h 32 min; on December 21 the figures are 8 h 34 min and 8 h 51 min. Month by month tables are on the Helena and Pierre daylight pages.
Where they sit
The border between them is also a Census region boundary: Montana is in the West and South Dakota in the Midwest. By county internal points, Montana spans 3 UTM zones and South Dakota 2.
Questions people ask
Which is bigger, Montana or South Dakota?
Montana, with 145,550 square miles of land against 75,808, 1.92 times as large.
Which has more people, Montana or South Dakota?
Montana has 1,137,233 residents, 23% more than South Dakota's 924,669.
How far is Helena from Pierre?
585 miles in a straight line, heading E (101°) from Helena.
Do Montana and South Dakota have counties with the same name?
Yes, 3: Custer, Lake, Lincoln.
Sources and data as of
Data as of: Census Vintage 2024 population estimates, 2024 Gazetteer land area and internal points, SAIPE 2023 median household income.
- 01Census Vintage 2024 county population estimates
- 02Census 2024 Gazetteer, counties
- 03Census SAIPE 2023 state and county estimates
- 04Census Bureau regions and divisions of the United States (last verified 2026-09-30)
How every number is computed: methodology. Spotted a wrong figure? Report an error.