• county
  • FIPS 39109
  • Largest town: Troy

Miami County, Ohio

Miami County had 111,950 residents in the Census Vintage 2024 estimate, on 406.6 square miles of land. It ranks 25th of 88 in Ohio by population and 70th by land area.

Population
111,950
#25 of 88 in Ohio · #572 in US
Area
406.6 sq mi
#70 of 88 in Ohio · #2,491 in US
Density
275 / sq mi
#22 of 88 in Ohio · #465 in US
Median household income
$75,735
#18 of 88 in Ohio · #632 in US

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

Miami County within Ohio. Pin: Columbus.

Measure from here

Tools and pages that start from Miami County

Miami County population, land area and income

Miami County had 111,950 residents in the Census Vintage 2024 estimate, on 406.6 square miles of land. It ranks 25th of 88 in Ohio by population and 70th by land area. That works out to 275.3 people per square mile, 2.9 times the US average of 96.3, and in the top quarter nationally.

The median county-equivalent in Ohio has 58,250 residents; Miami County is somewhat larger.

Its SAIPE 2023 median household income of $75,735 is in the top quarter among 3,143 counties with an estimate.

National rank among 3,144

Population

111,950

3144th1st

572nd of 3,144 (US)

Land area

407 sq mi

3144th1st

2491st of 3,144 (US)

Density

275.3 / sq mi

3144th1st

465th of 3,144 (US)

Median household income

$75,735

3143rd1st

632nd of 3,143 (US)

Rank within Ohio (88)

Population

111,950

88th1st

25th of 88 (OH)

Land area

407 sq mi

88th1st

70th of 88 (OH)

Density

275.3 / sq mi

88th1st

22nd of 88 (OH)

Median household income

$75,735

88th1st

18th of 88 (OH)

How Miami County's population changed since 2020

Miami County gained 2,988 residents between the July 2020 and July 2024 estimates, a rise of 2.7%. That ranks 8th 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, Miami County recorded 4,750 births and 5,673 deaths, a natural change of -923. Net international migration added +712 and net domestic migration, people moving to or from other US counties, came to +3,349. The largest single component was domestic migration, which added 3,349 people.

109.0k2020109.4k2021110.2k2022110.9k2023112.0k2024
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
4,750
Deaths
5,673
Net international migration
+712
Net domestic migration
+3,349
Change, July 2023 to July 2024
+1,052

Where Miami County is

The Census internal point of Miami County is at 40.053300, -84.228400. It sits in UTM zone 16N. The map shades Ohio's 88 county-equivalents by population change from 2020 to 2024, darker for faster growth, with Miami 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: Miami County internal point. Dark pin: Columbus.

Internal point

Decimal
40.053300, -84.228400
DMS
40°03'11.88"N 84°13'42.24"W
UTM
16N 736414.9E 4437354.2N
Geohash
dph5g76z2
Plus code
86GQ3Q3C+8J

Towns in Miami County

9 incorporated places of 1,000+ people have residents in Miami County, 74,305 people together, or 66% of the county. Each figure counts only the part of the town inside Miami County; towns marked "part" extend into another county. The largest is Troy with 27,122.

  1. 01Troy27,122
  2. 02Piqua20,940
  3. 03Tipp City10,596
  4. 04Huber Heights (part)5,789
  5. 05West Milton4,855
  6. 06Covington2,622
  7. 07Pleasant Hill1,266
  8. 08Bradford (part)1,076
  9. 09Union (part)39
Census Vintage 2024 subcounty estimates, county parts of incorporated places (SUMLEV 157).

Counties bordering Miami County

The Census 2024 county adjacency file lists 5 neighbors for Miami County. The most populous is Montgomery County, OH, with 537,443 residents. Distances run between Census internal points in a straight line.

Distance to Columbus and the nearest big city

Columbus is 65.3 miles E of Miami County's internal point in a straight line. The nearest place of 100,000 or more is Dayton, OH (population 136,346), 18.6 miles away. The nearest place of 10,000 or more is Troy, OH (population 27,122), 0.9 miles away.

Miami County FIPS code

The FIPS code of Miami County is 39109: state code 39 for Ohio plus county code 109. Use it as text, with the leading zero, when joining Census, BLS, or CDC county tables. SAIPE lists its 2023 median household income as $75,735.

Questions people ask

What is the population of Miami County, Ohio?

The Census Vintage 2024 estimate for July 1, 2024 is 111,950. That is up 2,988 people (2.7%) from the July 2020 estimate of 108,962.

What is the FIPS code of Miami County?

39109. The first two digits (39) are Ohio; the last three (109) identify the county.

What is the largest town in Miami County?

Troy, with 27,122 residents inside Miami County in 2024.

Which counties border Miami County?

5 county-equivalents border it in the Census 2024 adjacency file: Montgomery County, OH; Clark County, OH; Darke County, OH; Shelby County, OH; Champaign 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.