Jackson County area

Jackson County, South Dakota covers 1,871.3 square miles: 1,863.9 square miles of land and 7.377 square miles of water. Its county seat is Kadoka. An estimated 2,666 people lived there in 2025.

Official Census measurements · GEOID 460712026 Gazetteer · retrieved September 27, 2026
Land area1,863.9 mi²
Water area7.377 mi²
Population (2025)2,666
People per mi²1.4

County outline

Generalized outline of Jackson County, South Dakota
2025 Census cartographic boundary, fitted to this frame. County maps are not at a common scale. The 2026 area measurements below come from the separate Gazetteer release. Map source and limitations.

Where Jackson County is located

Jackson County highlighted on a map of all U.S. county equivalents. About the maps

Area breakdown

Land accounts for 99.6% of Jackson County’s measured area and water for 0.4%. Its combined area converts to 4,846.5 square kilometers or approximately 1,197,606 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land1,863.8834,827.4351,192,885.1
Water7.37719.1064,721.3
Total1,871.264,846.5411,197,606.4

How Jackson County compares

By original Census land area, Jackson County ranks #10 of 66 in South Dakota and #312 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 2.05 times the South Dakota county-equivalent median of 909.3 square miles. It accounts for 2.5% of the combined county land area in the state.

See the complete South Dakota ranking · What counts as a county equivalent?

Population and density of Jackson County

The Census Bureau estimates that 2,666 people lived in Jackson County on July 1, 2025. That ranks #3,060 of 3,222 county equivalents nationally and #51 of 66 in South Dakota. Since the April 1, 2020 estimates base of 2,804, the population has declined by 138 (−4.9%), compared with +5.5% for South Dakota as a whole.

With 1,863.9 square miles of land, that is 1.4 people per square mile (0.55 per km²), placing Jackson County #3,111 nationally for density and #60 in South Dakota. The median county equivalent has 47 people per square mile; the South Dakota median is 5.7. Put another way, there are about 447 acres of land per resident.

Estimated population, 2020–2025 · line scaled to this county’s own range
July 1202020212022202320242025
Estimate2,7992,8622,8292,7552,7162,666
Change—+63−33−74−39−50

U.S. Census Bureau, Vintage 2025 population estimates. Estimates are revised each year and are not decennial census counts. Density divides the whole population by the whole county’s land area, so it describes an average, not how settlement is distributed within the county. Population sources and methods.

Cities and towns in Jackson County

4 incorporated places lie at least partly in Jackson County. Together they are home to 630 people (23.6%); the other 2,036 (76.4%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Kadoka city, with 518 residents in the county.

Incorporated placePopulation 2025Since 2020Land mi²
Kadoka cityCounty seat518−4.8%2.285
Interior town63−6%1.339
Belvidere town40−4.8%0.76
Cottonwood town9−10%0.918

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Jackson County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.

Metropolitan area

Jackson County is not part of any metropolitan or micropolitan statistical area in the Office of Management and Budget’s July 2023 delineation; 1,306 other county equivalents are also outside one. These areas are built around an urban core of at least 10,000 people plus the counties tied to it by commuting, so counties outside them are generally rural.

ZIP codes

12 ZIP Code Tabulation Areas have land in Jackson County; 4 of them have most of their land inside the county, and the others mainly cover neighboring areas.

575215754357547575525756057567575775771457750577525777557790

ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Lighter codes have less than half of their land in this county. Post-office-box and single-address ZIP Codes have no tabulation area.

Counties bordering Jackson County

Jackson County shares a land border with 6 county equivalents. It has more land than 4 of them. The largest neighbor is Pennington County (2,776.8 mi²) and the smallest is Jones County (969.7 mi²). Together with its neighbors, Jackson County forms a block of 12,006.4 mi² of land, of which it holds 15.5%.

Map of Jackson County and the 6 county equivalents that border it Haakon County, South Dakota: 1,810.5 mi² landBennett County, South Dakota: 1,184.6 mi² landMellette County, South Dakota: 1,307.3 mi² landPennington County, South Dakota: 2,776.8 mi² landOglala Lakota County, South Dakota: 2,093.6 mi² landJones County, South Dakota: 969.7 mi² land
Jackson County (dark) and its bordering county equivalents. Select a neighbor to open its profile. Drawn from the 2025 Census cartographic boundaries in an equal-area projection. How borders are determined.
Bordering county equivalentLand mi²Size vs. JacksonCompare
Pennington County2,776.81.5× largerCompare
Oglala Lakota County2,093.61.1× largerCompare
Haakon County1,810.5about the sameCompare
Mellette County1,307.31.4× smallerCompare
Bennett County1,184.61.6× smallerCompare
Jones County969.71.9× smallerCompare

How big is Jackson County compared with U.S. states?

Jackson County has more land than 1 of the 50 states. It is about 1.8 times the land area of Rhode Island (1,033.9 mi²), while Delaware, the next larger state, has 1 times as much land (1,948.6 mi²). South Dakota’s county land could hold about 41 areas the size of Jackson County.

Land area: Jackson County and the closest-sized states
Rhode Island1,033.9 mi²
Jackson County1,863.9 mi²
Delaware1,948.6 mi²

Another way to picture it: the same land area would fill a square about 43.2 miles (69.5 km) on each side. Real county shapes are rarely square, so this is a scale reference rather than a width or driving distance.

State figures are the sums of each state’s county-equivalent land measurements in the same Census release, so states and counties are compared on the same basis. Published state totals can differ slightly because of rounding. Compare all states · Counties bigger than entire states.

What stands out about Jackson County?

Jackson County has more land than 2,910 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Jackson County1,863.9 mi²
South Dakota median909.3 mi²
National median604.5 mi²

A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.

Does including water change its rank?

Using land plus water places Jackson County at #351 nationally by total area, 39 places farther from the top than its land rank. Other county equivalents gain more area when their water measurements are included.

Its water share is 0.4%, compared with a national county-equivalent median of 1.2% — 0.8 percentage points lower. This describes the statistical geography’s land/water mix, not flood exposure or developable land.

Closest positions in the national land ranking

These entries sit immediately beside Jackson County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#311Fremont County, Idaho1,864Compare
#312Jackson County, South Dakota1,863.9This county
#313Sweet Grass County, Montana1,855.5Compare

Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.

Representative coordinates

The Census internal point is 43.677506, -101.626323. It represents a location inside the geography; it is not necessarily the centroid or the address of a courthouse.

Source and precision

U.S. Census Bureau, 2026 Gazetteer Files, Counties. Original ALAND: 4,827,433,505 m²; AWATER: 19,106,095 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.

Download the official county source ZIP ↗ · Methodology

Common questions

How big is Jackson County?

Jackson County, South Dakota has 1,863.9 square miles (4,827.4 km²) of land and 7.377 square miles of water, for a total area of 1,871.3 square miles. It ranks #312 of 3,222 U.S. county equivalents by land area.

Is Jackson County the largest county in South Dakota?

No. Jackson County ranks #10 of 66 in South Dakota by land area. The largest is Meade County, with 3,470.9 square miles of land.

What counties border Jackson County?

Jackson County shares a land border with Haakon County, Bennett County, Mellette County, Pennington County, Oglala Lakota County, and Jones County.

What is the population of Jackson County?

The Census Bureau estimates Jackson County had 2,666 residents on July 1, 2025, ranking #3,060 of 3,222 county equivalents. That is 1.4 people per square mile of land.

What is the county seat of Jackson County?

The county seat of Jackson County is Kadoka.

What cities and towns are in Jackson County?

Jackson County has 4 incorporated places. The most populous are Kadoka city, Interior town, Belvidere town, and Cottonwood town; 2,036 residents live outside any incorporated place.

Is Jackson County part of a metropolitan area?

No. Jackson County is outside every metropolitan and micropolitan statistical area in the July 2023 OMB delineation.

How many ZIP codes are in Jackson County?

12 ZIP Code Tabulation Areas have land in Jackson County, and 4 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.

How does Jackson County compare with U.S. states?

It has more land than 1 of the 50 states, including Rhode Island (1,033.9 square miles of land).

How many acres of land are in Jackson County?

The land measurement converts to approximately 1,192,885 acres. Including water, total area is approximately 1,197,606 acres. One square mile equals 640 acres.

Why might another source show a different area?

Check whether it reports land or total area, its Census vintage, and its rounding. Our guide explains how to reconcile county area figures.

Can this establish a property boundary?

No. Statistical measurements and generalized maps do not establish property lines. Consult the relevant local surveying or land-records authority.

Cite this county

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