Jefferson County Demographics

A map of Jefferson County's Population by Race

Race	2024 Pop	2020 Pop	2024 %	2020 %
White	12,941	13,425	82.4%	85.7%
Asian	1,285	500	8.2%	3.2%
Hispanic	644	610	4.1%	3.9%
Multiracial	395	583	2.5%	3.7%
Black	377	409	2.4%	2.6%
Native American/Other	63	136	0.4%	0.9%

Jefferson County, Iowa has an estimated population of 15,705, a less than 1% change from the 15,663 recorded in the 2020 Census. The population is 82.4% White, 8.2% Asian, 4.1% Hispanic, 2.5% Multiracial, 2.4% Black, and 0.4% Native American/Other. This demographic dot map shows the population of Jefferson County, with one dot drawn for each person counted by the Census, color-coded by race.

Jefferson has become considerably more racially diverse since the 2020 Census. It is about as diverse as Iowa overall. Demographers use a diversity index to measure the probability that two randomly selected individuals belong to different racial or ethnic groups. In Jefferson County, that probability was 26.1% in 2020 and 31.1% in the most recent ACS estimates.

Jefferson County is ranked the 48th most populous county in Iowa, out of 99 counties. Jefferson County was ranked the 48th most populous county in the 2020 Census.

Jefferson County's White Population

12,941 residents of Jefferson County, or 82.4% of the population, identify as White. The share of White residents in Jefferson County is comparable to the share in Iowa overall, where 82.3% of the population is White. Jefferson County ranks 76th statewide in terms of White residents as a share of the population, out of 99 counties.

Since the 2020 Census, Jefferson County's White population has declined by an estimated 3.6%. White residents' share of Jefferson County's population has decreased from 85.7% to 82.4%.

Jefferson County is more White than neighboring Wapello County (75.6% White). Jefferson County is less White than neighboring Van Buren County (94.4% White), Keokuk County (94.6% White), Washington County (88.7% White), and Henry County (86.2% White).

Jefferson County's Black Population

377 residents of Jefferson County, or 2.4% of the population, identify as Black. The share of Black residents in Jefferson County is comparable to the share in Iowa overall, where 3.8% of the population is Black. Jefferson County ranks 17th statewide in terms of Black residents as a share of the population, out of 99 counties.

Since the 2020 Census, Jefferson County's Black population has declined by an estimated 7.8%. Black residents' share of Jefferson County's population has remained roughly unchanged at 2.4%.

Jefferson County is more Black than neighboring Van Buren County (0.4% Black), Keokuk County (0.3% Black), and Washington County (1% Black). Jefferson County is less Black than neighboring Henry County (2.5% Black), and Wapello County (3% Black).

Jefferson County's Asian Population

1,285 residents of Jefferson County, or 8.2% of the population, identify as Asian. The share of Asian residents in Jefferson County is higher than in Iowa overall, where 2.5% of the population is Asian. Jefferson County ranks 7th statewide in terms of Asian residents as a share of the population, out of 99 counties.

Since the 2020 Census, Jefferson County's Asian population has grown by an estimated 157.0%. Asian residents' share of Jefferson County's population has increased from 3.2% to 8.2%.

Jefferson County is more Asian than neighboring Van Buren County (0% Asian), Keokuk County (0.2% Asian), Washington County (0.4% Asian), Henry County (0.9% Asian), and Wapello County (1.6% Asian).

Jefferson County's Hispanic Population

644 residents of Jefferson County, or 4.1% of the population, identify as Hispanic. The share of Hispanic residents in Jefferson County is slightly lower than in Iowa overall, where 7.3% of the population is Hispanic. Jefferson County ranks 40th statewide in terms of Hispanic residents as a share of the population, out of 99 counties.

Since the 2020 Census, Jefferson County's Hispanic population has grown by an estimated 5.6%. Hispanic residents' share of Jefferson County's population has remained roughly unchanged at 4.1%.

Jefferson County is more Hispanic than neighboring Van Buren County (1.8% Hispanic), and Keokuk County (2.3% Hispanic). Jefferson County is less Hispanic than neighboring Washington County (7.8% Hispanic), Henry County (5.5% Hispanic), and Wapello County (13.4% Hispanic).

Jefferson County's Native American/Other Population

63 residents of Jefferson County, or 0.4% of the population, identify as American Indian/Alaska Native/Native Hawaiian/Pacific Islander/Other. The share of Native American/Other residents in Jefferson County is comparable to the share in Iowa overall, where 0.6% of the population is Native American/Other. Jefferson County ranks 11th statewide in terms of Native American/Other residents as a share of the population, out of 99 counties.

Since the 2020 Census, Jefferson County's Native American/Other population has declined by an estimated 53.7%. Native American/Other residents' share of Jefferson County's population has decreased from 0.9% to 0.4%.

Jefferson County is more Native American/Other than neighboring Keokuk County (0.3% Native American/Other), and Washington County (0.2% Native American/Other). Jefferson County is less Native American/Other than neighboring Van Buren County (1% Native American/Other), and Wapello County (2.6% Native American/Other).

Jefferson County's Multiracial Population

395 residents of Jefferson County, or 2.5% of the population, identify as Multiracial. The share of Multiracial residents in Jefferson County is comparable to the share in Iowa overall, where 3.5% of the population is Multiracial. Jefferson County ranks 11th statewide in terms of Multiracial residents as a share of the population, out of 99 counties.

Since the 2020 Census, Jefferson County's Multiracial population has declined by an estimated 32.2%. Multiracial residents' share of Jefferson County's population has decreased from 3.7% to 2.5%.

Jefferson County is more Multiracial than neighboring Van Buren County (2.4% Multiracial), Keokuk County (2.3% Multiracial), and Washington County (2% Multiracial). Jefferson County is less Multiracial than neighboring Henry County (4.4% Multiracial), and Wapello County (3.7% 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.