Data / Population / Gallatin County

Population in Gallatin County

Population in Gallatin County was 128,740 in 2025, according to the U.S. Census Bureau. That is up 1% from 2024. That is the 2nd highest of 56 counties in 2025.

2025, persons128,740
Change on 2024+1%
Rank2nd of 56Counties in Montana ranked
Series high128,7402025
Series low119,5932020

Population in Gallatin County, 2020 to 2025

CSVChart (SVG)

118K120K122K124K126K128K130K2020202120222023202420252020: 119,593 persons2021: 123,103 persons2022: 124,713 persons2023: 125,952 persons2024: 127,498 persons2025: 128,740 persons
persons. Source: U.S. Census Bureau. Retrieved 2026-10-08, published 2026-03-26.
All 6 values
Periodpersons
2025128,740
2024127,498
2023125,952
2022124,713
2021123,103
2020119,593

Compared with Montana and United States

Place2025
Gallatin County128,740
Montana1,144,694
United States341,784,857

Rankings

Definition

Resident population. Spain and the EU: 1 January, with Spanish figures from the official municipal register (Padrón). United States: Census Bureau population estimates for 1 July. Other countries and the World: World Bank mid-year estimates, which count all residents regardless of legal status or citizenship.

For Denmark, Statistics Denmark counts the registered resident population on 1 January. Greenland and the Faroe Islands are excluded. The annual series selects the first-quarter reference date from FOLK1A. The World Bank series exists for every country, so use it (through compare) to rank countries on one basis.

How to cite

U.S. Census Bureau. Annual estimates of the resident population for the United States, states and counties, 1 July (Population Estimates Program). https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-08.

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Questions

What is the population in Gallatin County?

Population in Gallatin County was 128,740 in 2025, according to the U.S. Census Bureau. That is up 1% from 2024. That is the 2nd highest of 56 counties in 2025.

Where does this figure come from?

U.S. Census Bureau. Annual estimates of the resident population for the United States, states and counties, 1 July (Population Estimates Program). Retrieved by Invokely on 2026-10-08.

What was the highest population in Gallatin County?

128,740 in 2025, the highest value since 2020 in this series.

More statistics for Gallatin County

All statistics for Gallatin County