Data / Population density / St. Louis County

Population density in St. Louis County

Population density in St. Louis County was 752.4 inhabitants per km² in 2025, according to the U.S. Census Bureau. That is down 0.1% from 2024. That is the 2nd highest of 115 counties in 2025.

2025, inhabitants per km²752.4
Change on 2024-0.1%
Rank2nd of 115Counties in Missouri ranked
Series high761.82020
Series low751.62023

Population density in St. Louis County, 2020 to 2025

CSVChart (SVG)

7507537557587607632020202120222023202420252020: 761.8 inhabitants per km²2021: 758.4 inhabitants per km²2022: 753 inhabitants per km²2023: 751.6 inhabitants per km²2024: 752.9 inhabitants per km²2025: 752.4 inhabitants per km²
inhabitants per km². Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-09, published 2026-03-26.
All 6 values
Periodinhabitants per km²
2025752.4
2024752.9
2023751.6
2022753
2021758.4
2020761.8

Compared with Missouri and United States

Place2025
St. Louis County752.4
Missouri35.2
United States37.3

Rankings

Definition

Resident population divided by land area in km². World Bank figures use mid-year population and land area excluding inland water.

United States: Census Bureau population estimates for 1 July divided by land area (water excluded) from the latest Census Gazetteer files. US tables often give people per square mile; multiply persons per km² by 2.59 to compare.

How to cite

U.S. Census Bureau. Population Estimates Program resident population on 1 July divided by land area from the latest Census Gazetteer files, persons per km². https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-09.

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Questions

What is the population density in St. Louis County?

Population density in St. Louis County was 752.4 inhabitants per km² in 2025, according to the U.S. Census Bureau. That is down 0.1% from 2024. That is the 2nd highest of 115 counties in 2025.

Where does this figure come from?

U.S. Census Bureau. Population Estimates Program resident population on 1 July divided by land area from the latest Census Gazetteer files, persons per km². Retrieved by Invokely on 2026-10-09.

What was the highest population density in St. Louis County?

761.8 inhabitants per km² in 2020, the highest value since 2020 in this series.

More statistics for St. Louis County

All statistics for St. Louis County