Mountain Plains, South Dakota Demographics & Population 2026

A note before these figures: with a population of 350, Mountain Plains'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

Mountain Plains is a small community located in South Dakota, within Lawrence County. The total population is 350. It ranks as the 182nd most populous out of 439 Census-designated places in South Dakota.

Age Demographics

The median age in Mountain Plains is 63.4 years. This is 67% higher than the state median of 38.0 years.

Economy, Income & Housing

The median household income in Mountain Plains is $248,558. This is 231% higher than the state median of $75,081. It is also 208% higher than the national median of $80,734. The ACS records no residents below the poverty line in Mountain Plains. In a community this small the estimate rests on very few survey responses, so it should be read as an absence of measurement rather than a measured absence of poverty. The unemployment rate is 14.7%. This is 401% higher than the state rate of 2.9%. The median home value is $613,200. Housing costs are 138% higher than the state median of $257,400. With a home-value-to-income ratio of just 2.5x, Mountain Plains is one of the most affordable housing markets in the area. 100.0% of occupied housing units are owner-occupied. This homeownership rate is 46% higher than the state average of 68.6%.

Race & Ethnicity

The largest racial or ethnic group in Mountain Plains is White (non-Hispanic), making up 82.9% of the population. Asian residents account for 7.4%. The Hispanic or Latino population (0.6%) is well below the state average of 4.8%. The Asian population is significantly higher than the state average (7.4% vs 1.4%).

Education

43.1% of residents aged 25 and older hold a bachelor's degree or higher. This places Mountain Plains in the top 10% of all cities in the state for educational attainment. This is 35% higher than the state rate of 31.9%. Nationally, 35.7% of adults hold at least a bachelor's degree. No surveyed resident aged 25 or older reported leaving school before earning a high school diploma, though a rate of exactly 100% reflects the limits of a small sample.

Data Sources & Methodology

All demographic data for Mountain Plains, 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.