Marion County Demographics
A map of Marion County's Population by Race
Marion County, Iowa has an estimated population of 33,642, a less than 1% change from the 33,414 recorded in the 2020 Census. The population is 93.3% White, 2.3% Hispanic, 2.3% Multiracial, 1.4% Asian, 0.4% Black, and 0.3% Native American/Other. This demographic dot map shows the population of Marion County, with one dot drawn for each person counted by the Census, color-coded by race.
Marion has become less racially diverse since the 2020 Census. It is considerably less diverse than Iowa overall. Demographers use a diversity index to measure the probability that two randomly selected individuals belong to different racial or ethnic groups. In Marion County, that probability was 14.2% in 2020 and 12.8% in the most recent ACS estimates.
Marion County is ranked the 21st most populous county in Iowa, out of 99 counties. Marion County was ranked the 22nd most populous county in the 2020 Census.
Marion County's White Population
31,393 residents of Marion County, or 93.3% of the population, identify as White. The share of White residents in Marion County is considerably higher than in Iowa overall, where 82.3% of the population is White. Marion County ranks 44th statewide in terms of White residents as a share of the population, out of 99 counties.
Since the 2020 Census, Marion County's White population has grown by an estimated 1.5%. White residents' share of Marion County's population has increased from 92.5% to 93.3%.
Marion County is more White than neighboring Jasper County (90.8% White), Mahaska County (91.6% White), and Warren County (91.9% White). Marion County is less White than neighboring Lucas County (94% White), and Monroe County (94.8% White).
Marion County's Black Population
141 residents of Marion County, or 0.4% of the population, identify as Black. The share of Black residents in Marion County is slightly lower than in Iowa overall, where 3.8% of the population is Black. Marion County ranks 45th statewide in terms of Black residents as a share of the population, out of 99 counties.
Since the 2020 Census, Marion County's Black population has declined by an estimated 49.8%. Black residents' share of Marion County's population has remained roughly unchanged at 0.4%.
Marion County is more Black than neighboring Lucas County (0.3% Black). Marion County is less Black than neighboring Jasper County (1.5% Black), Monroe County (1.2% Black), Mahaska County (1.1% Black), and Warren County (0.7% Black).
Marion County's Asian Population
473 residents of Marion County, or 1.4% of the population, identify as Asian. The share of Asian residents in Marion County is comparable to the share in Iowa overall, where 2.5% of the population is Asian. Marion County ranks 19th statewide in terms of Asian residents as a share of the population, out of 99 counties.
Since the 2020 Census, Marion County's Asian population has grown by an estimated 18.0%. Asian residents' share of Marion County's population has remained roughly unchanged at 1.4%.
Marion County is more Asian than neighboring Jasper County (0.7% Asian), Lucas County (0.8% Asian), Monroe County (0.5% Asian), Mahaska County (1% Asian), and Warren County (0.7% Asian).
Marion County's Hispanic Population
773 residents of Marion County, or 2.3% of the population, identify as Hispanic. The share of Hispanic residents in Marion County is slightly lower than in Iowa overall, where 7.3% of the population is Hispanic. Marion County ranks 80th statewide in terms of Hispanic residents as a share of the population, out of 99 counties.
Since the 2020 Census, Marion County's Hispanic population has grown by an estimated 10.4%. Hispanic residents' share of Marion County's population has remained roughly unchanged at 2.3%.
Marion County is more Hispanic than neighboring Monroe County (2.1% Hispanic). Marion County is less Hispanic than neighboring Jasper County (3.1% Hispanic), Lucas County (2.9% Hispanic), Mahaska County (2.5% Hispanic), and Warren County (3.7% Hispanic).
Marion County's Native American/Other Population
90 residents of Marion County, or 0.3% of the population, identify as American Indian/Alaska Native/Native Hawaiian/Pacific Islander/Other. The share of Native American/Other residents in Marion County is comparable to the share in Iowa overall, where 0.6% of the population is Native American/Other. Marion County ranks 40th statewide in terms of Native American/Other residents as a share of the population, out of 99 counties.
Since the 2020 Census, Marion County's Native American/Other population has declined by an estimated 47.4%. Native American/Other residents' share of Marion County's population has remained roughly unchanged at 0.3%.
Marion County is more Native American/Other than neighboring Lucas County (0% Native American/Other), and Warren County (0.2% Native American/Other). Marion County is less Native American/Other than neighboring Monroe County (0.4% Native American/Other), and Mahaska County (0.4% Native American/Other).
Marion County's Multiracial Population
772 residents of Marion County, or 2.3% of the population, identify as Multiracial. The share of Multiracial residents in Marion County is comparable to the share in Iowa overall, where 3.5% of the population is Multiracial. Marion County ranks 32nd statewide in terms of Multiracial residents as a share of the population, out of 99 counties.
Since the 2020 Census, Marion County's Multiracial population has declined by an estimated 18.1%. Multiracial residents' share of Marion County's population has decreased from 2.8% to 2.3%.
Marion County is more Multiracial than neighboring Lucas County (2% Multiracial), and Monroe County (1.1% Multiracial). Marion County is less Multiracial than neighboring Jasper County (3.6% Multiracial), Mahaska County (3.4% Multiracial), and Warren County (2.8% Multiracial).
Sources: Most recent population estimates are from the 2020-2024 American Community Survey 5-Year Estimates. 2020 population counts and map data are from 2020 Census State Redistricting Data. Geographic data are from Census TIGER/Line Shapefiles.