• county
  • FIPS 39147
  • Largest town: Tiffin

Seneca County, Ohio

Seneca County had 54,730 residents in the Census Vintage 2024 estimate, on 551.0 square miles of land. It ranks 47th of 88 in Ohio by population and 16th by land area.

Population
54,730
#47 of 88 in Ohio · #949 in US
Area
551.0 sq mi
#16 of 88 in Ohio · #1,896 in US
Density
99 / sq mi
#55 of 88 in Ohio · #916 in US
Median household income
$62,966
#49 of 88 in Ohio · #1,563 in US

Census Vintage 2024 estimates · SAIPE 2023 income · 2024 Gazetteer land area

Seneca County within Ohio. Pin: Columbus.

Measure from here

Tools and pages that start from Seneca County

Seneca County population, land area and income

Seneca County had 54,730 residents in the Census Vintage 2024 estimate, on 551.0 square miles of land. It ranks 47th of 88 in Ohio by population and 16th by land area. That works out to 99.3 people per square mile, near the US average of 96.3, and above the national county median.

The median county-equivalent in Ohio has 58,250 residents, about the same as Seneca County.

Its SAIPE 2023 median household income of $62,966 is above the national county median among 3,143 counties with an estimate.

National rank among 3,144

Population

54,730

3144th1st

949th of 3,144 (US)

Land area

551 sq mi

3144th1st

1896th of 3,144 (US)

Density

99.3 / sq mi

3144th1st

916th of 3,144 (US)

Median household income

$62,966

3143rd1st

1563rd of 3,143 (US)

Rank within Ohio (88)

Population

54,730

88th1st

47th of 88 (OH)

Land area

551 sq mi

88th1st

16th of 88 (OH)

Density

99.3 / sq mi

88th1st

55th of 88 (OH)

Median household income

$62,966

88th1st

49th of 88 (OH)

How Seneca County's population changed since 2020

Seneca County lost 325 residents between the July 2020 and July 2024 estimates, a drop of 0.6%. That ranks 54th of 88 in Ohio for growth. The median Ohio county changed by -0.2%, and the state as a whole by +0.7%.

Since the April 2020 estimates base, Seneca County recorded 2,531 births and 2,948 deaths, a natural change of -417. Net international migration added +341 and net domestic migration, people moving to or from other US counties, came to -282. The largest single component was natural change, which removed 417 people.

55.1k202054.9k202154.6k202254.6k202354.7k2024
Census Vintage 2024 county estimates for July 1 of each year. The axis starts above zero so year-to-year changes are visible.

Components of change, April 2020 to July 2024

Births
2,531
Deaths
2,948
Net international migration
+341
Net domestic migration
-282
Change, July 2023 to July 2024
+102

Where Seneca County is

The Census internal point of Seneca County is at 41.120000, -83.127500. It sits in UTM zone 17N. The map shades Ohio's 88 county-equivalents by population change from 2020 to 2024, darker for faster growth, with Seneca County outlined. Dots are towns of 1,000+ people with residents in it.

Shelby County: -0.4%Defiance County: +1.0%Darke County: -0.8%Seneca County: -0.6%Wood County: +0.6%Fayette County: -0.7%Clark County: -0.7%Hocking County: -2.2%Jackson County: +0.2%Miami County: +2.7%Richland County: -0.1%Union County: +13.7%Auglaize County: -1.2%Hancock County: +0.1%Morgan County: -1.6%Van Wert County: -0.1%Hardin County: -1.0%Paulding County: -0.3%Portage County: +1.2%Delaware County: +10.6%Harrison County: -3.1%Ross County: -1.3%Crawford County: -0.9%Clinton County: -0.0%Henry County: -0.5%Pike County: -0.0%Cuyahoga County: -1.7%Highland County: +1.0%Knox County: +1.7%Ottawa County: -1.5%Huron County: -0.6%Erie County: -2.2%Holmes County: +1.0%Lawrence County: -4.0%Marion County: -0.6%Fairfield County: +5.2%Putnam County: -0.6%Guernsey County: -0.5%Vinton County: -2.1%Gallia County: -1.2%Trumbull County: -0.7%Wayne County: -0.2%Perry County: +0.6%Ashland County: -0.1%Fulton County: -1.4%Brown County: +1.4%Lucas County: -1.1%Stark County: -0.1%Medina County: +1.1%Belmont County: -2.4%Williams County: -1.4%Mahoning County: -1.0%Noble County: +1.1%Greene County: +2.5%Preble County: -0.5%Allen County: -1.2%Athens County: +1.3%Jefferson County: -2.0%Adams County: +0.8%Monroe County: -2.3%Washington County: -2.2%Logan County: -0.1%Franklin County: +2.4%Warren County: +5.3%Wyandot County: -2.1%Licking County: +3.4%Hamilton County: +0.8%Clermont County: +2.6%Butler County: +2.2%Coshocton County: +1.1%Geauga County: -0.0%Sandusky County: -0.0%Ashtabula County: -0.6%Carroll County: -0.9%Tuscarawas County: -1.2%Morrow County: +2.7%Montgomery County: +0.1%Mercer County: +0.3%Lake County: -0.1%Pickaway County: +6.0%Madison County: +3.8%Muskingum County: +0.1%Meigs County: -3.0%Columbiana County: -1.8%Lorain County: +2.7%Scioto County: -2.8%Champaign County: +0.4%Summit County: -0.3%
Change 2020 to 2024
  1. < -1.4%
  2. < -0.6%
  3. < -0.0%
  4. < +1.1%
  5. ≥ +1.1%
no data

Orange pin: Seneca County internal point. Dark pin: Columbus.

Internal point

Decimal
41.120000, -83.127500
DMS
41°07'12.00"N 83°07'39.00"W
UTM
17N 321393.3E 4554259.6N
Geohash
dpkcumsmk
Plus code
86HR4VCF+22

Towns in Seneca County

3 incorporated places of 1,000+ people have residents in Seneca County, 27,473 people together, or 50% of the county. Each figure counts only the part of the town inside Seneca County; towns marked "part" extend into another county. The largest is Tiffin with 17,729.

  1. 01Tiffin17,729
  2. 02Fostoria (part)9,101
  3. 03Green Springs (part)643
Census Vintage 2024 subcounty estimates, county parts of incorporated places (SUMLEV 157).

Counties bordering Seneca County

The Census 2024 county adjacency file lists 6 neighbors for Seneca County. The most populous is Wood County, OH, with 133,077 residents. Distances run between Census internal points in a straight line.

Distance to Columbus and the nearest big city

Columbus is 80.3 miles S of Seneca County's internal point in a straight line. The nearest place of 100,000 or more is Toledo, OH (population 265,638), 44.4 miles away. The nearest place of 10,000 or more is Tiffin, OH (population 17,729), 2.8 miles away.

Seneca County FIPS code

The FIPS code of Seneca County is 39147: state code 39 for Ohio plus county code 147. Use it as text, with the leading zero, when joining Census, BLS, or CDC county tables. SAIPE lists its 2023 median household income as $62,966.

Questions people ask

What is the population of Seneca County, Ohio?

The Census Vintage 2024 estimate for July 1, 2024 is 54,730. That is down 325 people (0.6%) from the July 2020 estimate of 55,055.

What is the FIPS code of Seneca County?

39147. The first two digits (39) are Ohio; the last three (147) identify the county.

What is the largest town in Seneca County?

Tiffin, with 17,729 residents inside Seneca County in 2024.

Which counties border Seneca County?

6 county-equivalents border it in the Census 2024 adjacency file: Wood County, OH; Hancock County, OH; Sandusky County, OH; Huron County, OH; Crawford County, OH; Wyandot County, OH.

Sources and data as of

Data as of: Census Vintage 2024 population estimates, 2024 Gazetteer land area and internal points, SAIPE 2023 median household income.

  1. 01Census Vintage 2024 county population estimates
  2. 02Census 2024 Gazetteer, counties
  3. 03Census SAIPE 2023 state and county estimates
  4. 04Census Vintage 2024 subcounty population estimates
  5. 05Census 2024 county adjacency file
  6. 06Census 2024 cartographic boundary file, counties (1:5,000,000)

How every number is computed: methodology. Spotted a wrong figure? Report an error.