The map above shows Montana and South Dakota side by side at exactly the same scale, using equal-area projections, so their true relative sizes are preserved.
Montana vs South Dakota Geography
Land area
- Montana has a land area of 145,550 square miles (376,973 km²), while South Dakota has 75,808 square miles (196,342 km²).
- Montana's land area is 1.9 times (92%) larger than South Dakota's.
Total area
- Montana: 147,043 square miles (380,840 km²) vs South Dakota: 77,116 square miles (199,729 km²), including inland and coastal water.
- Montana's total area is 1.9 times (91%) larger than South Dakota's.
Length
- Montana is 319 miles (514 km) long from north to south; South Dakota is 443 miles (712 km).
- South Dakota's north-south length is 1.4 times (39%) longer than Montana's.
Width
- Montana spans 607 miles (976 km) east to west; South Dakota spans 371 miles (597 km).
- Montana's east-west width is 1.6 times (64%) wider than South Dakota's.
Highest point
- Montana's highest point is Granite Peak at 12,767 feet (3,891 m); South Dakota's is Black Elk Peak at 7,198 feet (2,194 m).
- Granite Peak is 5,569 feet higher than Black Elk Peak.
Lowest point
- Montana's lowest point is Kootenai River at 1,805 feet; South Dakota's is Big Stone Lake at 966 feet.
- South Dakota's lowest point is 839 feet lower.
Montana vs South Dakota Population and History
Population
- Montana has a population of 1,137,233 (2024), while South Dakota has 924,669 (2024).
- Montana's population is 1.2 times (23%) larger than South Dakota's.
Population density
- Montana: 7.8 people per square mile vs South Dakota: 12.2.
- South Dakota's population density is 1.6 times (56%) higher than Montana's.
Biggest city
- Montana's biggest city is Billings with 121,483 people; South Dakota's is Sioux Falls with 209,289.
- Sioux Falls' population is 1.7 times (72%) larger than Billings'.
Largest metro area
- Montana's largest metropolitan area is Billings, MT metro area (192,531 people) vs South Dakota's Sioux Falls, SD-MN metro area (308,266).
- Sioux Falls, SD-MN metro area's population is 1.6 times (60%) larger than Billings, MT metro area's.
History
- Montana: Admitted to the Union on November 8, 1889, as the 41st state.
- South Dakota: Admitted to the Union on November 2, 1889, as the 40th state.
Montana vs South Dakota Economy
GDP
- Montana's GDP is $78.4 billion (2024) vs South Dakota's $76.8 billion.
- Montana and South Dakota have about the same economic output.
GDP per capita
- Montana: $68,975 per person vs South Dakota: $83,052.
- South Dakota's GDP per capita is 1.2 times (20%) higher than Montana's.
Average income
- Montana: $69,240 vs South Dakota: $75,699 average income per person (per capita personal income).
- South Dakota's average income is 1.1 times (9%) higher than Montana's.
Montana vs South Dakota Counties
Number of counties
- Montana has 56 counties, while South Dakota has 66.
- South Dakota's county count is 1.2 times (18%) higher than Montana's.
Biggest county by area
- Montana's largest county is Beaverhead County at 5,543 square miles; South Dakota's is Meade County at 3,471 square miles.
- Beaverhead County's land area is 1.6 times (60%) larger than Meade County's.
Smallest county by area
- Montana: Silver Bow County (718 sq mi) vs South Dakota: Clay County (412 sq mi).
- Silver Bow County's land area is 1.7 times (74%) larger than Clay County's.
Most populous county
- Montana: Yellowstone County (171,583 people) vs South Dakota: Minnehaha County (208,639 people).
- Minnehaha County's population is 1.2 times (22%) larger than Yellowstone County's.
Least populous county
- Montana: Petroleum County (525 people) vs South Dakota: Jones County (874 people).
- Jones County's population is 1.7 times (66%) larger than Petroleum County's.
Richest county
- Montana: Gallatin County ($94,573 per capita income) vs South Dakota: Union County ($146,712).
- Union County's income is 1.6 times (55%) richer than Gallatin County's.
Poorest county
- Montana: Blaine County ($37,554 per capita income) vs South Dakota: Ziebach County ($32,778).
- Blaine County's income is 1.1 times (15%) richer than Ziebach County's.
Montana vs South Dakota Taxes
State income tax
- Montana has a top income tax rate of 5.65%, while South Dakota has no state income tax.
- Montana's top rate is 5.65 percentage points higher.
Property tax
- Montana: 0.69% effective rate vs South Dakota: 1.02% of home value per year.
- South Dakota's rate is 0.33 percentage points higher.
Sales tax
- Montana: 0% combined state and average local rate vs South Dakota: 6.11%.
- South Dakota's combined rate is 6.11 percentage points higher.
Official Websites
Montana official website · South Dakota official website
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More Size Comparisons
All Montana size comparisons · All South Dakota size comparisons
Area, elevation and boundary figures come from official national statistics and US Census Bureau and Natural Earth boundary data; US state population, economic, county and tax figures come from the US Census Bureau, the Bureau of Economic Analysis and the Tax Foundation. Figures are rounded and for general reference.