Buchanan County Demographics

A map of Buchanan County's Population by Race

Race	2024 Pop	2020 Pop	2024 %	2020 %
White	19,649	19,565	95.0%	95.1%
Multiracial	451	494	2.2%	2.4%
Hispanic	400	338	1.9%	1.6%
Black	124	70	0.6%	0.3%
Asian	40	52	0.2%	0.3%
Native American/Other	30	46	0.1%	0.2%

Buchanan County, Iowa has an estimated population of 20,694, a less than 1% change from the 20,565 recorded in the 2020 Census. The population is 95.0% White, 2.2% Multiracial, 1.9% Hispanic, 0.6% Black, 0.2% Asian, and 0.1% Native American/Other. This demographic dot map shows the population of Buchanan County, with one dot drawn for each person counted by the Census, color-coded by race.

Buchanan is about as racially diverse as it was in 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 Buchanan County, that probability was 9.4% in 2020 and 9.8% in the most recent ACS estimates.

Buchanan County is ranked the 31st most populous county in Iowa, out of 99 counties. Buchanan County was ranked the 32nd most populous county in the 2020 Census.

Buchanan County's White Population

19,649 residents of Buchanan County, or 95.0% of the population, identify as White. The share of White residents in Buchanan County is considerably higher than in Iowa overall, where 82.3% of the population is White. Buchanan County ranks 10th statewide in terms of White residents as a share of the population, out of 99 counties.

Since the 2020 Census, Buchanan County's White population has remained roughly the same. White residents' share of Buchanan County's population has remained roughly unchanged at 95.0%.

Buchanan County is more White than neighboring Fayette County (91% White), Benton County (94.4% White), Linn County (82.4% White), Delaware County (94.1% White), and Black Hawk County (78.1% White).

Buchanan County's Black Population

124 residents of Buchanan County, or 0.6% of the population, identify as Black. The share of Black residents in Buchanan County is slightly lower than in Iowa overall, where 3.8% of the population is Black. Buchanan County ranks 79th statewide in terms of Black residents as a share of the population, out of 99 counties.

Since the 2020 Census, Buchanan County's Black population has grown by an estimated 77.1%. Black residents' share of Buchanan County's population has remained roughly unchanged at 0.6%.

Buchanan County is more Black than neighboring Benton County (0.4% Black), and Delaware County (0.1% Black). Buchanan County is less Black than neighboring Fayette County (0.8% Black), Linn County (5.9% Black), and Black Hawk County (9.1% Black).

Buchanan County's Asian Population

40 residents of Buchanan County, or 0.2% of the population, identify as Asian. The share of Asian residents in Buchanan County is slightly lower than in Iowa overall, where 2.5% of the population is Asian. Buchanan County ranks 83rd statewide in terms of Asian residents as a share of the population, out of 99 counties.

Since the 2020 Census, Buchanan County's Asian population has declined by an estimated 23.1%. Asian residents' share of Buchanan County's population has remained roughly unchanged at 0.2%.

Buchanan County is more Asian than neighboring Delaware County (0% Asian). Buchanan County is less Asian than neighboring Fayette County (0.9% Asian), Linn County (2.4% Asian), and Black Hawk County (2.7% Asian).

Buchanan County's Hispanic Population

400 residents of Buchanan County, or 1.9% of the population, identify as Hispanic. The share of Hispanic residents in Buchanan County is lower than in Iowa overall, where 7.3% of the population is Hispanic. Buchanan County ranks 88th statewide in terms of Hispanic residents as a share of the population, out of 99 counties.

Since the 2020 Census, Buchanan County's Hispanic population has grown by an estimated 18.3%. Hispanic residents' share of Buchanan County's population has remained roughly unchanged at 1.9%.

Buchanan County is more Hispanic than neighboring Delaware County (1.7% Hispanic). Buchanan County is less Hispanic than neighboring Fayette County (3.1% Hispanic), Benton County (2% Hispanic), Linn County (4.1% Hispanic), and Black Hawk County (5.2% Hispanic).

Buchanan County's Native American/Other Population

30 residents of Buchanan County, or 0.1% of the population, identify as American Indian/Alaska Native/Native Hawaiian/Pacific Islander/Other. The share of Native American/Other residents in Buchanan County is comparable to the share in Iowa overall, where 0.6% of the population is Native American/Other. Buchanan County ranks 90th statewide in terms of Native American/Other residents as a share of the population, out of 99 counties.

Since the 2020 Census, Buchanan County's Native American/Other population has declined by an estimated 34.8%. Native American/Other residents' share of Buchanan County's population has remained roughly unchanged at 0.1%.

Buchanan County is less Native American/Other than neighboring Fayette County (0.5% Native American/Other), Benton County (0.2% Native American/Other), Linn County (0.5% Native American/Other), Delaware County (0.5% Native American/Other), and Black Hawk County (1% Native American/Other).

Buchanan County's Multiracial Population

451 residents of Buchanan County, or 2.2% of the population, identify as Multiracial. The share of Multiracial residents in Buchanan County is comparable to the share in Iowa overall, where 3.5% of the population is Multiracial. Buchanan County ranks 60th statewide in terms of Multiracial residents as a share of the population, out of 99 counties.

Since the 2020 Census, Buchanan County's Multiracial population has declined by an estimated 8.7%. Multiracial residents' share of Buchanan County's population has remained roughly unchanged at 2.2%.

Buchanan County is less Multiracial than neighboring Fayette County (3.7% Multiracial), Benton County (2.8% Multiracial), Linn County (4.7% Multiracial), Delaware County (3.7% Multiracial), and Black Hawk County (3.9% 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.