Population of Counties in Ohio (2020)

In 2019, Ohio's Franklin County, home of Columbus, has the highest population in the state with 1,310,300 residents. This represents growth of 12.35% since the last census. The next-largest counties are Cuyahoga County (1,243,857) with the city of Cleveland, Hamilton County (816,684) with the city of Cincinnati, Summit County (541,918), and Montgomery County (532,331). These are the only counties in Ohio exceeding 500,000 residents. Of these counties, Franklin County experienced the most rapid growth while Cuyahoga County experienced growth of -2.68%.

Ohio Counties with Fewest Residents

There are no counties in Ohio with fewer than 10,000 residents. The least populated county in Ohio is Vinton County with 13,139, a decline of 1.98%. Other small counties in Ohio include Monroe County (13,790), Noble County (14,354), Morgan County (14,604), Harrison County (15,174), and Paulding County (18,760). All of these counties have experienced a decline in population. Monroe County had the largest decline of 5.60%. Of Ohio's 39 counties with a population below 50,000, all but five experienced a decline in population ranging from -0.02% to -6.12% in the case of Carroll County.

Ohio Counties with Rapid Growth

Delaware County, Ohio experienced the most rapid growth in the state since the last census, climbing 16.98% to 204,826 residents in 2019. Other cities with major growth include Franklin County (12.35%), Union County (10.35%), Warren County (8.77%), and Fairfield County (6.41%). The county with the most rapid decline is Carroll County at -6.12% population growth followed by Jefferson County (-5.60%), Monroe County (-5.60%), and Trumbull County (-5.34%).

Name 2020 Population Growth Since 2010
Franklin County1,310,30012.35%
Cuyahoga County1,243,860-2.68%
Hamilton County816,6841.80%
Summit County541,9180.05%
Montgomery County532,331-0.61%
Lucas County429,899-2.61%
Butler County382,3783.60%
Stark County371,574-1.01%
Lorain County309,4612.65%
Warren County232,1738.77%
Lake County230,5140.22%
Mahoning County229,642-3.67%
Clermont County205,4663.98%
Delaware County204,82616.98%
Trumbull County198,627-5.34%
Medina County179,1463.85%
Licking County175,7695.44%
Greene County167,9953.96%
Portage County162,9270.95%
Fairfield County155,7826.41%
Clark County134,585-2.67%
Wood County130,6963.77%
Richland County121,099-2.46%
Wayne County115,9671.38%
Miami County106,2223.65%
Columbiana County102,665-4.84%
Allen County102,663-3.48%
Ashtabula County97,493-3.85%
Geauga County94,0310.68%
Tuscarawas County92,176-0.41%
Muskingum County86,183-0.03%
Ross County76,931-1.50%
Hancock County75,9301.66%
Scioto County75,502-5.03%
Erie County74,615-3.08%
Belmont County67,505-4.03%
Athens County65,8180.99%
Jefferson County65,767-5.60%
Marion County65,256-1.80%
Knox County61,8931.31%
Washington County60,155-2.52%
Lawrence County59,866-4.10%
Sandusky County58,799-3.43%
Huron County58,504-1.77%
Pickaway County58,0864.21%
Union County57,83510.35%
Seneca County55,207-2.49%
Ashland County53,7450.79%
Darke County51,323-3.10%
Shelby County48,627-1.39%
Auglaize County45,804-0.27%
Logan County45,358-0.85%
Madison County44,4132.25%
Holmes County43,8923.34%
Brown County43,602-2.82%
Highland County43,058-1.28%
Fulton County42,276-0.83%
Clinton County42,0570.35%
Crawford County41,550-5.04%
Preble County40,997-2.79%
Mercer County40,9590.42%
Ottawa County40,769-1.42%
Guernsey County39,022-2.79%
Champaign County38,754-3.30%
Defiance County38,165-2.36%
Williams County36,804-1.87%
Coshocton County36,629-0.83%
Perry County36,033-0.02%
Morrow County35,1120.92%
Putnam County33,780-2.02%
Jackson County32,384-2.62%
Hardin County31,480-2.00%
Gallia County29,979-3.52%
Fayette County28,666-1.21%
Hocking County28,385-3.71%
Van Wert County28,281-1.38%
Pike County28,067-2.36%
Adams County27,724-2.91%
Henry County27,086-3.85%
Carroll County27,081-6.12%
Meigs County23,106-2.64%
Wyandot County21,935-2.89%
Paulding County18,760-4.08%
Harrison County15,174-4.11%
Morgan County14,604-2.92%
Noble County14,354-2.09%
Monroe County13,790-5.60%
Vinton County13,139-1.98%