Seneca County Demographics

A map of Seneca County's Population by Race

Race	2024 Pop	2020 Pop	2024 %	2020 %
White	48,097	48,213	87.8%	87.6%
Hispanic	3,123	2,899	5.7%	5.3%
Multiracial	1,654	2,024	3.0%	3.7%
Black	1,299	1,314	2.4%	2.4%
Native American/Other	309	260	0.6%	0.5%
Asian	288	359	0.5%	0.7%

Seneca County, Ohio has an estimated population of 54,770, a less than 1% change from the 55,069 recorded in the 2020 Census. The population is 87.8% White, 5.7% Hispanic, 3.0% Multiracial, 2.4% Black, 0.6% Native American/Other, and 0.5% Asian. This demographic dot map shows the population of Seneca County, with one dot drawn for each person counted by the Census, color-coded by race.

Seneca is about as racially diverse as it was in the 2020 Census. It is considerably less diverse than Ohio overall. Demographers use a diversity index to measure the probability that two randomly selected individuals belong to different racial or ethnic groups. In Seneca County, that probability was 22.9% in 2020 and 22.4% in the most recent ACS estimates.

Seneca County is ranked the 47th most populous county in Ohio, out of 88 counties. Seneca County was ranked the 47th most populous county in the 2020 Census.

Seneca County's White Population

48,097 residents of Seneca County, or 87.8% of the population, identify as White. The share of White residents in Seneca County is considerably higher than in Ohio overall, where 75.8% of the population is White. Seneca County ranks 54th statewide in terms of White residents as a share of the population, out of 88 counties.

Since the 2020 Census, Seneca County's White population has remained roughly the same. White residents' share of Seneca County's population has remained roughly unchanged at 87.8%.

Seneca County is more White than neighboring Sandusky County (81.9% White), and Huron County (87.5% White). Seneca County is less White than neighboring Wyandot County (94.1% White), Crawford County (94% White), and Ottawa County (90.3% White).

Seneca County's Black Population

1,299 residents of Seneca County, or 2.4% of the population, identify as Black. The share of Black residents in Seneca County is lower than in Ohio overall, where 12% of the population is Black. Seneca County ranks 36th statewide in terms of Black residents as a share of the population, out of 88 counties.

Since the 2020 Census, Seneca County's Black population has declined by an estimated 1.1%. Black residents' share of Seneca County's population has remained roughly unchanged at 2.4%.

Seneca County is more Black than neighboring Wyandot County (0.2% Black), Crawford County (0.7% Black), Ottawa County (1% Black), and Huron County (0.8% Black). Seneca County is less Black than neighboring Sandusky County (2.8% Black).

Seneca County's Asian Population

288 residents of Seneca County, or 0.5% of the population, identify as Asian. The share of Asian residents in Seneca County is comparable to the share in Ohio overall, where 2.5% of the population is Asian. Seneca County ranks 31st statewide in terms of Asian residents as a share of the population, out of 88 counties.

Since the 2020 Census, Seneca County's Asian population has declined by an estimated 19.8%. Asian residents' share of Seneca County's population has remained roughly unchanged at 0.5%.

Seneca County is more Asian than neighboring Wyandot County (0% Asian), Ottawa County (0.4% Asian), and Huron County (0.4% Asian). Seneca County is less Asian than neighboring Crawford County (0.8% Asian).

Seneca County's Hispanic Population

3,123 residents of Seneca County, or 5.7% of the population, identify as Hispanic. The share of Hispanic residents in Seneca County is comparable to the share in Ohio overall, where 4.8% of the population is Hispanic. Seneca County ranks 16th statewide in terms of Hispanic residents as a share of the population, out of 88 counties.

Since the 2020 Census, Seneca County's Hispanic population has grown by an estimated 7.7%. Hispanic residents' share of Seneca County's population has remained roughly unchanged at 5.7%.

Seneca County is more Hispanic than neighboring Wyandot County (3.1% Hispanic), Crawford County (1.8% Hispanic), and Ottawa County (5.3% Hispanic). Seneca County is less Hispanic than neighboring Sandusky County (10.9% Hispanic), and Huron County (7.4% Hispanic).

Seneca County's Native American/Other Population

309 residents of Seneca County, or 0.6% of the population, identify as American Indian/Alaska Native/Native Hawaiian/Pacific Islander/Other. The share of Native American/Other residents in Seneca County is comparable to the share in Ohio overall, where 0.5% of the population is Native American/Other. Seneca County ranks 47th statewide in terms of Native American/Other residents as a share of the population, out of 88 counties.

Since the 2020 Census, Seneca County's Native American/Other population has grown by an estimated 18.8%. Native American/Other residents' share of Seneca County's population has remained roughly unchanged at 0.6%.

Seneca County is more Native American/Other than neighboring Sandusky County (0.5% Native American/Other), Wyandot County (0.2% Native American/Other), Crawford County (0.1% Native American/Other), Ottawa County (0.4% Native American/Other), and Huron County (0.5% Native American/Other).

Seneca County's Multiracial Population

1,654 residents of Seneca County, or 3.0% of the population, identify as Multiracial. The share of Multiracial residents in Seneca County is comparable to the share in Ohio overall, where 4.3% of the population is Multiracial. Seneca County ranks 49th statewide in terms of Multiracial residents as a share of the population, out of 88 counties.

Since the 2020 Census, Seneca County's Multiracial population has declined by an estimated 18.3%. Multiracial residents' share of Seneca County's population has decreased from 3.7% to 3.0%.

Seneca County is more Multiracial than neighboring Wyandot County (2.4% Multiracial), Crawford County (2.5% Multiracial), and Ottawa County (2.7% Multiracial). Seneca County is less Multiracial than neighboring Sandusky County (3.3% Multiracial), and Huron County (3.4% 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.