Mercer County Demographics

A map of Mercer County's Population by Race

Race	2024 Pop	2020 Pop	2024 %	2020 %
White	14,426	14,578	93.1%	92.9%
Hispanic	534	468	3.4%	3.0%
Multiracial	368	503	2.4%	3.2%
Black	93	68	0.6%	0.4%
Asian	56	37	0.4%	0.2%
Native American/Other	18	45	0.1%	0.3%

Mercer County, Illinois has an estimated population of 15,495, a slight decrease from the 15,699 recorded in the 2020 Census. The population is 93.1% White, 3.4% Hispanic, 2.4% Multiracial, 0.6% Black, 0.4% Asian, and 0.1% Native American/Other. This demographic dot map shows the population of Mercer County, with one dot drawn for each person counted by the Census, color-coded by race.

Mercer is about as racially diverse as it was in the 2020 Census. It is considerably less diverse than Illinois overall. Demographers use a diversity index to measure the probability that two randomly selected individuals belong to different racial or ethnic groups. In Mercer County, that probability was 13.6% in 2020 and 13.1% in the most recent ACS estimates.

Mercer County is ranked the 69th most populous county in Illinois, out of 102 counties. Mercer County was ranked the 69th most populous county in the 2020 Census.

Mercer County's White Population

14,426 residents of Mercer County, or 93.1% of the population, identify as White. The share of White residents in Mercer County is significantly higher than in Illinois overall, where 58.1% of the population is White. Mercer County ranks 31st statewide in terms of White residents as a share of the population, out of 102 counties.

Since the 2020 Census, Mercer County's White population has declined by an estimated 1.0%. White residents' share of Mercer County's population has remained roughly unchanged at 93.1%.

Mercer County is more White than neighboring Rock Island County (67.4% White), Warren County (81.1% White), Scott County (77% White), and Muscatine County (75% White). Mercer County is less White than neighboring Henderson County (93.7% White).

Mercer County's Black Population

93 residents of Mercer County, or 0.6% of the population, identify as Black. The share of Black residents in Mercer County is considerably lower than in Illinois overall, where 13.3% of the population is Black. Mercer County ranks 85th statewide in terms of Black residents as a share of the population, out of 102 counties.

Since the 2020 Census, Mercer County's Black population has grown by an estimated 36.8%. Black residents' share of Mercer County's population has remained roughly unchanged at 0.6%.

Mercer County is more Black than neighboring Henderson County (0.3% Black). Mercer County is less Black than neighboring Rock Island County (10.9% Black), Warren County (2.7% Black), Scott County (7.1% Black), and Muscatine County (2.2% Black).

Mercer County's Asian Population

56 residents of Mercer County, or 0.4% of the population, identify as Asian. The share of Asian residents in Mercer County is lower than in Illinois overall, where 5.9% of the population is Asian. Mercer County ranks 90th statewide in terms of Asian residents as a share of the population, out of 102 counties.

Since the 2020 Census, Mercer County's Asian population has grown by an estimated 51.4%. Asian residents' share of Mercer County's population has remained roughly unchanged at 0.4%.

Mercer County is more Asian than neighboring Henderson County (0.2% Asian). Mercer County is less Asian than neighboring Rock Island County (2.6% Asian), Warren County (2.4% Asian), Scott County (2.8% Asian), and Muscatine County (0.6% Asian).

Mercer County's Hispanic Population

534 residents of Mercer County, or 3.4% of the population, identify as Hispanic. The share of Hispanic residents in Mercer County is significantly lower than in Illinois overall, where 18.8% of the population is Hispanic. Mercer County ranks 52nd statewide in terms of Hispanic residents as a share of the population, out of 102 counties.

Since the 2020 Census, Mercer County's Hispanic population has grown by an estimated 14.1%. Hispanic residents' share of Mercer County's population has remained roughly unchanged at 3.4%.

Mercer County is more Hispanic than neighboring Henderson County (1.2% Hispanic). Mercer County is less Hispanic than neighboring Rock Island County (14.2% Hispanic), Warren County (11.1% Hispanic), Scott County (7.4% Hispanic), and Muscatine County (18.8% Hispanic).

Mercer County's Native American/Other Population

18 residents of Mercer 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 Mercer County is comparable to the share in Illinois overall, where 0.5% of the population is Native American/Other. Mercer County ranks 89th statewide in terms of Native American/Other residents as a share of the population, out of 102 counties.

Since the 2020 Census, Mercer County's Native American/Other population has declined by an estimated 60.0%. Native American/Other residents' share of Mercer County's population has remained roughly unchanged at 0.1%.

Mercer County is less Native American/Other than neighboring Rock Island County (0.5% Native American/Other), Warren County (0.6% Native American/Other), Henderson County (1.2% Native American/Other), Scott County (0.6% Native American/Other), and Muscatine County (0.3% Native American/Other).

Mercer County's Multiracial Population

368 residents of Mercer County, or 2.4% of the population, identify as Multiracial. The share of Multiracial residents in Mercer County is comparable to the share in Illinois overall, where 3.4% of the population is Multiracial. Mercer County ranks 61st statewide in terms of Multiracial residents as a share of the population, out of 102 counties.

Since the 2020 Census, Mercer County's Multiracial population has declined by an estimated 26.8%. Multiracial residents' share of Mercer County's population has decreased from 3.2% to 2.4%.

Mercer County is more Multiracial than neighboring Warren County (2.1% Multiracial). Mercer County is less Multiracial than neighboring Rock Island County (4.4% Multiracial), Henderson County (3.5% Multiracial), Scott County (5.1% Multiracial), and Muscatine County (3.1% 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.