Is population growing or shrinking?

Refreshed annually
It grew by 29 between 2024 and 2025. Changes in population can reflect birth and death rates, immigration patterns, regional shifts, and even the overall health of the economy. The 0.17% annual increase was primarily driven by births outpacing deaths.
In the decade between 2015 and 2025, Union County, SD’s population grew by 16.5%.

+29

population change (2024 to 2025)

+0.17%

percent change in population (2024 to 2025)
Since 2000, Union County, SD’s population increased 22 out of 25 years. The largest increase occurred between 2019 and 2020, when Union County, SD gained 852 residents. Its largest decline occurred between 2014 and 2015 when there were 62 fewer residents.

Union County, SD gained 29 residents between 2024 and 2025.

Annual population change, 2001–2025

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What contributes to population change in Union County, SD?

A county’s population is influenced by three factors:
  • Natural population change: If births outnumber deaths in a given year, natural population growth is positive. If deaths exceed births, it is negative. Between 2024 and 2025 natural population change was positive in Union County, SD, with births exceeding deaths by 104.
  • Immigration: international migration directly into or out of a county: If more people move in than move out, population change from immigration is positive. If more people move out than move in, it’s negative. Between 2024 to 2025, Union County, SD’s population change from immigration was positive with about 39 more people coming from another country directly to Union County, SD than leaving.
  • Domestic migration, moving between counties: Between 2024 to 2025, Union County, SD’s population change from domestic migration was negative with about 115 more people moving to any other county in the US.

Between 2024 and 2025, natural change was the primary driver of population growth in Union County, SD.

Components of population change from previous year, 2011–2025

How is the US population changing?

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Methodology

USAFacts standardizes data, in areas such as time and demographics, to make it easier to understand and compare.

Page sources

USAFacts endeavors to share the most up-to-date information available. We sourced the data on this page directly from government agencies; however, the intervals at which agencies publish updated data vary.