Data / Population / Marion, IA

Population in Marion, IA

Population in Marion, IA was 42,732 in 2025, according to the U.S. Census Bureau. That is up 0.9% from 2024. That is the 13th highest of 41 cities in 2025.

2025, persons42,732
Change on 2024+0.9%
Rank13th of 41Cities in Iowa ranked
Series high42,7322025
Series low41,5712020

Next release: Friday, 14 May 2027, estimated by Invokely from past publication dates (low confidence), not announced by the publisher. Release calendar

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Population in Marion, IA, 2020 to 2025

41.5K41.8K42K42.3K42.5K42.8K2020202120222023202420252020: 41,571 persons2021: 41,668 persons2022: 41,605 persons2023: 42,025 persons2024: 42,353 persons2025: 42,732 persons
persons. Source: U.S. Census Bureau, Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals). Retrieved 2026-10-12, published 2026-05-14.
All 6 values
Periodpersons
202542,732
202442,353
202342,025
202241,605
202141,668
202041,571

Compared with Iowa and United States

Place2025
Marion, IA42,732
Iowa3,238,387
United States341,784,857

Rankings

Definition

Resident population. Spain and the EU: 1 January, with Spanish figures from the official municipal register (Padrón). Norway: Statistics Norway, 1 January. Iceland and its municipalities: Statistics Iceland, 1 January. United States: Census Bureau population estimates for 1 July. United Kingdom regions and local authorities: Office for National Statistics estimates for 30 June. Other countries and the World: World Bank mid-year estimates, which count all residents regardless of legal status or citizenship. UN World Population Prospects estimates for 1 July cover the years before 1960 and the areas the World Bank does not publish, such as Taiwan.

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 incorporated places, 1 July (Population Estimates Program, subcounty totals). https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-12.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

U.S. Census Bureau. (2026). Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals) (Population, Marion, IA, 2020 to 2025) [Data set]. Retrieved October 12, 2026, from https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/

MLA 9

Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals), Population, Marion, IA, 2020 to 2025. U.S. Census Bureau, 14 May 2026, https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Invokely, https://invokely.ai/en/population/marion-ia. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Census Bureau. 2026. Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals). Population, Marion, IA, 2020 to 2025. Dataset. Accessed October 12, 2026. https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Also distributed by Invokely, https://invokely.ai/en/population/marion-ia.

Harvard

U.S. Census Bureau (2026) Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals), Population, Marion, IA, 2020 to 2025 [Dataset]. Available at: https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/, via Invokely: https://invokely.ai/en/population/marion-ia (Accessed: 12 October 2026).

BibTeX
@misc{census_population_marion_ia_2025,
  author = {{U.S. Census Bureau}},
  title = {{Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals): Population, Marion, IA, 2020 to 2025}},
  year = {2026},
  howpublished = {Data set},
  url = {https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/en/population/marion-ia. Publisher attribution: U.S. Census Bureau. Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals). https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-12.},
}
RIS
TY  - DATA
AU  - U.S. Census Bureau
TI  - Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals): Population, Marion, IA, 2020 to 2025
PY  - 2026
DA  - 2026/05/14
PB  - U.S. Census Bureau
DB  - Invokely
UR  - https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/
L2  - https://invokely.ai/en/population/marion-ia
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/population/marion-ia.
N1  - Publisher attribution: U.S. Census Bureau. Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals). https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-12.
ER  -
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Questions

What is the population in Marion, IA?

Population in Marion, IA was 42,732 in 2025, according to the U.S. Census Bureau. That is up 0.9% from 2024. That is the 13th highest of 41 cities in 2025.

Where does this figure come from?

U.S. Census Bureau. Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals). Retrieved by Invokely on 2026-10-12.

What was the highest population in Marion, IA?

42,732 in 2025, the highest value since 2020 in this series.

Population elsewhere in Iowa

Related statistics for Marion, IA

All statistics for Marion, IA | Marion, IA in figures