Data / Population / Mason County

Population in Mason County

Population in Mason County was 12,411 in 2025, according to the U.S. Census Bureau. That is down 0.6% from 2024. That is the 82nd highest of 102 counties in 2025.

2025, persons12,411
Change on 2024-0.6%
Rank82nd of 102Counties in Illinois ranked
Series high13,0502020
Series low12,4112025

Population in Mason County, 2020 to 2025

CSVChart (SVG)

12.4K12.6K12.8K13K13.2K2020202120222023202420252020: 13,050 persons2021: 12,826 persons2022: 12,710 persons2023: 12,580 persons2024: 12,489 persons2025: 12,411 persons
persons. Source: U.S. Census Bureau. Retrieved 2026-10-08, published 2026-03-26.
All 6 values
Periodpersons
202512,411
202412,489
202312,580
202212,710
202112,826
202013,050

Compared with Illinois and United States

Place2025
Mason County12,411
Illinois12,719,141
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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What is the latest population in Mason County? Cite the source.
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Questions

What is the population in Mason County?

Population in Mason County was 12,411 in 2025, according to the U.S. Census Bureau. That is down 0.6% from 2024. That is the 82nd highest of 102 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 Mason County?

13,050 in 2020, the highest value since 2020 in this series.

More statistics for Mason County

All statistics for Mason County