City in Jefferson County, Missouri · 11.5 sq mi · 1,824 people per sq mi
About 21,000 people live in Arnold. The typical household earns $78,370, and the median resident is 39.7 years old.
2026 projection
From 20,907 in 2020
Poverty rate 8.17%
Men 38.4 · Women 41.8
1960–2026
21,029
2026 projection
0.6% since 2020 (increase)
Source: U.S. Census Bureau decennial counts and annual estimates. 2026 is a projection. Values between recorded years are interpolated.
Use the left and right arrow keys to inspect population observations.
1960–2026
21,029
2026 projection
0.6% since 2020 (increase)
Source: U.S. Census Bureau decennial counts and annual estimates. 2026 is a projection. Values between recorded years are interpolated.
Use the left and right arrow keys to inspect population observations.
| 2026 | 21,029 | +35 | 0.17% |
|---|---|---|---|
| 2025 | 20,994 | -54 | 0.26% |
| 2024 | 21,048 | -49 | 0.23% |
| 2023 | 21,097 | +220 | 1.05% |
| 2022 | 20,877 | -29 | 0.14% |
| 2021 | 20,906 | -1 | 0.00% |
| 2020 | 20,907 | -227 | 1.07% |
| 2019 | 21,134 | -24 | 0.11% |
| 2018 | 21,158 | -9 | 0.04% |
| 2017 | 21,167 | -11 | 0.05% |
Showing 10 of 22 years.
U.S. Census Bureau, 2024 ACS 5-year estimates · Table S0101
Each square is about 1% of residents (roughly 210 people).
Hispanic or Latino residents can be of any race. All other groups exclude Hispanic residents.
U.S. Census Bureau, 2024 ACS 5-year estimates · Table B03002
Half of households earn more, half earn less
Typical yearly pay for a worker 25 or older.
About 1 in 12 residents
50% of residents age 15 and older are married.
| Status | Overall | Male | Female |
|---|---|---|---|
| Married | 50% | 54% | 47% |
| Never married | 28% | 28% | 27% |
| Divorced | 14% | 12% | 15% |
| Widowed | 7% | 3% | 10% |
| Separated | 2% | 3% | 1% |
U.S. Census Bureau, 2024 ACS 5-year estimates · Table S1201
10 sources, all from the U.S. Census Bureau