Rock County Demographics

A map of Rock County's Population by Race

Rock County, Wisconsin had a population of 163,687 in 2020. It was 79.3% White, 4.9% Black, 1.2% Asian, 9.7% Hispanic, 0.6% Native American/Other, and 4.3% Multiracial. This map presents the population of Rock County, with one dot drawn for each person counted in the 2020 Census, color-coded by race.

Rock County is the 9th most populous county of the 72 counties in Wisconsin.

Rock County's White Population

129,796 residents of Rock County identify as White, or 79.3%. This makes the White share of the population of Rock County roughly similar to the White share of the population of Wisconsin (78.6% White). Of the 72 counties in Wisconsin, Rock County is ranked #64 in terms of White residents as a share of the population.

Rock County is more White than neighboring Winnebago County (64.2% White), Boone County (68.6% White), and Dane County (76% White). Rock County is less White than neighboring Jefferson County (86.4% White), and Walworth County (82.7% White).

Rock County's Black Population

8,060 residents of Rock County identify as Black, or 4.9%. This makes the Black share of the population of Rock County roughly similar to the Black share of the population of Wisconsin (6.2% Black). Of the 72 counties in Wisconsin, Rock County is ranked #5 in terms of Black residents as a share of the population.

Rock County is more Black than neighboring Boone County (2.2% Black), Jefferson County (1% Black), and Walworth County (1.1% Black). Rock County is less Black than neighboring Winnebago County (13.4% Black), and Dane County (5.3% Black).

Rock County's Asian Population

2,022 residents of Rock County identify as Asian, or 1.2%. This makes the Asian share of the population of Rock County roughly similar to the Asian share of the population of Wisconsin (3% Asian). Of the 72 counties in Wisconsin, Rock County is ranked #20 in terms of Asian residents as a share of the population.

Rock County is more Asian than neighboring Jefferson County (0.8% Asian), and Walworth County (0.9% Asian). Rock County is less Asian than neighboring Winnebago County (2.8% Asian), and Dane County (6.3% Asian).

Rock County's Hispanic Population

15,800 residents of Rock County identify as Hispanic, or 9.7%. This makes the Hispanic share of the population of Rock County roughly similar to the Hispanic share of the population of Wisconsin (7.6% Hispanic). Of the 72 counties in Wisconsin, Rock County is ranked #7 in terms of Hispanic residents as a share of the population.

Rock County is more Hispanic than neighboring Jefferson County (8.3% Hispanic), and Dane County (7.5% Hispanic). Rock County is less Hispanic than neighboring Winnebago County (14.4% Hispanic), Boone County (24.1% Hispanic), and Walworth County (11.8% Hispanic).

Rock County's Native American/Other Population

959 residents of Rock County identify as American Indian/Alaska Native/Native Hawaiian/Pacific Islander/Other, or 0.6%. This makes the Native American/Other share of the population of Rock County roughly similar to the Native American/Other share of the population of Wisconsin (1.2% Native American/Other). Of the 72 counties in Wisconsin, Rock County is ranked #48 in terms of Native American/Other residents as a share of the population.

Rock County is more Native American/Other than neighboring Boone County (0.5% Native American/Other), Jefferson County (0.5% Native American/Other), and Walworth County (0.5% Native American/Other).

Rock County's Multiracial Population

7,050 residents of Rock County identify as Multiracial, or 4.3%. This makes the Multiracial share of the population of Rock County roughly similar to the Multiracial share of the population of Wisconsin (3.5% Multiracial). Of the 72 counties in Wisconsin, Rock County is ranked #8 in terms of Multiracial residents as a share of the population.

Rock County is more Multiracial than neighboring Boone County (3.4% Multiracial), Jefferson County (3% Multiracial), and Walworth County (3% Multiracial). Rock County is less Multiracial than neighboring Winnebago County (4.6% Multiracial).

Source: 2020 Census State Redistricting Data and Census TIGER/Line Shapefiles.