The map above shows South Dakota and Washington side by side at exactly the same scale, using equal-area projections, so their true relative sizes are preserved.
South Dakota vs Washington Geography
Land area: South Dakota has a land area of 75,808 square miles (196,342 km²), while Washington has 66,455 square miles (172,119 km²). South Dakota's land area is 1.1 times (14%) larger than Washington's.
Total area: South Dakota: 77,116 square miles (199,729 km²) vs Washington: 71,301 square miles (184,668 km²), including inland and coastal water. South Dakota's total area is 1.1 times (8%) larger than Washington's.
Length: South Dakota is 443 miles (712 km) long from north to south; Washington is 238 miles (383 km). South Dakota's north-south length is 1.9 times (86%) longer than Washington's.
Width: South Dakota spans 371 miles (597 km) east to west; Washington spans 399 miles (641 km). Washington's east-west width is 1.1 times (8%) wider than South Dakota's.
Highest point: South Dakota's highest point is Black Elk Peak at 7,198 feet (2,194 m); Washington's is Mount Rainier at 14,409 feet (4,392 m). Mount Rainier is 7,211 feet higher than Black Elk Peak.
Lowest point: South Dakota's lowest point is Big Stone Lake at 966 feet; Washington's is Pacific Ocean at 0 feet. Washington's lowest point is 966 feet lower.
South Dakota vs Washington Population and History
Population: South Dakota has a population of 924,669 (2024), while Washington has 7,958,180 (2024). Washington's population is 8.6 times (761%) larger than South Dakota's.
Population density: South Dakota: 12.2 people per square mile vs Washington: 119.8. Washington's population density is 9.8 times (882%) higher than South Dakota's.
Biggest city: South Dakota's biggest city is Sioux Falls with 209,289 people; Washington's is Seattle with 780,995. Seattle's population is 3.7 times (273%) larger than Sioux Falls'.
Largest metro area: South Dakota's largest metropolitan area is Sioux Falls, SD-MN metro area (308,266 people) vs Washington's Seattle-Tacoma-Bellevue, WA metro area (4,145,494). Seattle-Tacoma-Bellevue, WA metro area's population is 13.4 times larger than Sioux Falls, SD-MN metro area's.
History: South Dakota: Admitted to the Union on November 2, 1889, as the 40th state. Washington: Admitted to the Union on November 11, 1889, as the 42nd state.
South Dakota vs Washington Economy
GDP: South Dakota's GDP is $76.8 billion (2024) vs Washington's $856.0 billion. Washington's economic output is 11.1 times larger than South Dakota's.
GDP per capita: South Dakota: $83,052 per person vs Washington: $107,564. Washington's GDP per capita is 1.3 times (30%) higher than South Dakota's.
Average income: South Dakota: $75,699 vs Washington: $85,187 average income per person (per capita personal income). Washington's average income is 1.1 times (13%) higher than South Dakota's.
South Dakota vs Washington Counties
Number of counties: South Dakota has 66 counties, while Washington has 39. South Dakota's county count is 1.7 times (69%) higher than Washington's.
Biggest county by area: South Dakota's largest county is Meade County at 3,471 square miles; Washington's is Okanogan County at 5,266 square miles. Okanogan County's land area is 1.5 times (52%) larger than Meade County's.
Smallest county by area: South Dakota: Clay County (412 sq mi) vs Washington: San Juan County (174 sq mi). Clay County's land area is 2.4 times (137%) larger than San Juan County's.
Most populous county: South Dakota: Minnehaha County (208,639 people) vs Washington: King County (2,340,211 people). King County's population is 11.2 times larger than Minnehaha County's.
Least populous county: South Dakota: Jones County (874 people) vs Washington: Garfield County (2,404 people). Garfield County's population is 2.8 times (175%) larger than Jones County's.
Richest county: South Dakota: Union County ($146,712 per capita income) vs Washington: King County ($128,684). Union County's income is 1.1 times (14%) richer than King County's.
Poorest county: South Dakota: Ziebach County ($32,778 per capita income) vs Washington: Ferry County ($50,456). Ferry County's income is 1.5 times (54%) richer than Ziebach County's.
South Dakota vs Washington Taxes
State income tax: South Dakota has no state income tax, while Washington has a 9% tax on capital gains only.
Property tax: South Dakota: 1.02% effective rate vs Washington: 0.79% of home value per year. South Dakota's rate is 0.23 percentage points higher.
Sales tax: South Dakota: 6.11% combined state and average local rate vs Washington: 9.57%. Washington's combined rate is 3.46 percentage points higher.
Official Websites
South Dakota official website · Washington official website
More Size Comparisons
All South Dakota size comparisons · All Washington 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.