Keystone, South Dakota Demographics & Population 2026
During the 2020–2024 ACS period, Keystone, South Dakota had a total population of 336, the 188th largest town in South Dakota, with a median household income of $64,702, which is 14% lower than the state average. The poverty rate is 6.9%.
Data vintage: U.S. Census Bureau ACS 2020–2024 5-Year Estimates · refreshed July 2026 · Methodology & source notes
Keystone Quick Facts
How Keystone Changed
Change from the 2019–2023 ACS period to 2020–2024. These are rolling five-year estimates, not year-over-year measurements.
| Metric | 2019–2023 | 2020–2024 | Change |
|---|---|---|---|
| Population | 404 | 336 | -16.8% |
| Median household income | $62,159 | $64,702 | +4.1% |
| Median home value | $188,800 | $263,900 | +39.8% |
How Keystone Compares
Median Household Income
Median Home Value
Economy & Housing
Household Income Distribution
Detailed income brackets
Employment
Housing Overview
People & Demographics
Age Distribution
Race & Ethnicity
Diversity Index
Moderate diversity with one or two groups making up the majority.
State average: 35 | National average: 61
Education
Educational Attainment (Adults 25+)
Keystone Rankings in South Dakota
Explore South Dakota Rankings
Other Cities in Pennington County
| City | Population | Median Income | Poverty | Home Value |
|---|---|---|---|---|
| Rapid City | 77,946 | $70,870 | 12.5% | $299,400 |
| Box Elder | 12,902 | $73,008 | 7.5% | $302,100 |
| Rapid Valley | 6,975 | $83,208 | 4.5% | $255,500 |
| Colonial Pine Hills | 2,609 | $98,696 | 0.2% | $406,500 |
| Green Valley | 1,642 | $81,582 | 1.0% | $280,300 |
| Ashland Heights | 1,105 | $57,353 | 30.7% | $219,600 |
| Hill City | 834 | $95,385 | 2.6% | $286,200 |
| Johnson Siding | 704 | $102,716 | 10.2% | $471,700 |
| Wall | 622 | $58,984 | 8.8% | $164,800 |
| New Underwood | 509 | $56,250 | 25.8% | $193,800 |
Cities Similar to Keystone
These cities in the same state have comparable population and economic profiles.
| City | Population | Median Income | Home Value | Bachelor's+ | Poverty |
|---|---|---|---|---|---|
| Spring Creek | 330 | N/A | N/A | 0.0% | 93.3% |
| Hoven | 329 | $60,625 | $88,300 | 14.6% | 6.9% |
| Ethan | 346 | $60,417 | $152,300 | 17.1% | 12.1% |
| Alpena | 317 | $66,667 | $51,800 | 5.8% | 6.6% |
| Presho | 313 | $63,393 | $162,500 | 26.8% | 0.0% |
A note before these figures: with a population of 336, Keystone's ACS estimates come from a small number of survey responses and carry wide margins of error. Individual percentages below — particularly rates that round to 0% or 100% — are approximations, not precise measurements. See data.census.gov for the published margins of error.
Population Overview
Keystone is a small community located in South Dakota, within Pennington County. The total population is 336. It ranks as the 188th most populous out of 439 Census-designated places in South Dakota.
Age Demographics
The median age in Keystone is 38.1 years. This is about the same as the state median of 38.0 years. With 29.2% of the population under 18, Keystone has a notably young demographic profile, suggesting a family-oriented community.
Economy, Income & Housing
The median household income in Keystone is $64,702. This is 14% lower than the state median of $75,081. It is also 20% lower than the national median of $80,734. The poverty rate stands at 6.9%. This is 43% lower than the state poverty rate of 11.9%. The unemployment rate is 7.8%. This is 165% higher than the state rate of 2.9%. The median home value is $263,900. Housing costs are 3% higher than the state median of $257,400. The home-value-to-income ratio is 4.1x. 70.1% of occupied housing units are owner-occupied. This homeownership rate is 2% higher than the state average of 68.6%.
Race & Ethnicity
The largest racial or ethnic group in Keystone is White (non-Hispanic), making up 63.7% of the population. Hispanic or Latino residents account for 23.8%. The Hispanic or Latino population is significantly higher than the state average (23.8% vs 4.8%). The Asian population (0.6%) is well below the state average of 1.4%.
Education
13.5% of residents aged 25 and older hold a bachelor's degree or higher. This is 58% lower than the state rate of 31.9%. Nationally, 35.7% of adults hold at least a bachelor's degree. The high school graduation rate (or equivalent) is 84.7%.
Data Sources & Methodology
All demographic data for Keystone, South Dakota is sourced from the U.S. Census Bureau's American Community Survey (ACS) 2020–2024 5-Year Estimates. The ACS collects data from approximately 3.5 million households annually and pools five years of responses so that even small communities can be measured, though the margin of error widens as the population falls. Comparisons are made against South Dakota state averages and national averages calculated from the same dataset. Rankings reflect the city's position among all 439 Census-designated places in South Dakota. Read more about how these figures are produced on our methodology page, or visit data.census.gov for official data.
Free data download: Get all South Dakota city and county demographics as CSV. Download Cities CSV | Download Counties CSV
Frequently Asked Questions
What is the population of Keystone, South Dakota?
Keystone, South Dakota has a population of 336 according to the most recent U.S. Census ACS 5-Year Estimates.
What is the median household income in Keystone, SD?
The median household income in Keystone is $64,702, which is 20% lower than the national median of $80,734.
What is the poverty rate in Keystone, SD?
The poverty rate in Keystone is 6.9%. This means approximately 23 residents live below the federal poverty line.
What is the racial makeup of Keystone, South Dakota?
Keystone's population is 63.7% White, 0.0% Black, 23.8% Hispanic/Latino, and 0.6% Asian.
What is the median home value in Keystone, SD?
The median home value in Keystone is $263,900. The home-value-to-income ratio is 4.1x.
How educated is Keystone, South Dakota?
13.5% of adults (25+) in Keystone hold a bachelor's degree or higher, and 5.1% hold a graduate or professional degree.