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 County1,339,49014.85%
Cuyahoga County1,234,830-3.39%
Hamilton County820,7102.30%
Summit County542,2700.12%
Montgomery County533,655-0.36%
Lucas County427,631-3.13%
Butler County385,4484.43%
Stark County370,568-1.28%
Lorain County313,1393.87%
Warren County238,80111.88%
Lake County230,8020.34%
Mahoning County228,906-3.97%
Delaware County213,39421.87%
Clermont County208,0565.29%
Trumbull County195,253-6.95%
Medina County180,9584.90%
Licking County179,9677.96%
Greene County170,4275.47%
Portage County163,5311.33%
Fairfield County158,2328.08%
Clark County134,457-2.76%
Wood County131,0244.03%
Richland County122,211-1.57%
Wayne County115,4070.89%
Miami County108,1365.52%
Allen County101,851-4.24%
Columbiana County101,697-5.74%
Ashtabula County97,095-4.25%
Geauga County94,2010.87%
Tuscarawas County91,706-0.91%
Muskingum County86,2530.05%
Ross County76,153-2.50%
Hancock County76,0521.82%
Scioto County74,710-6.03%
Erie County74,131-3.71%
Belmont County66,603-5.31%
Marion County65,886-0.86%
Jefferson County64,569-7.32%
Athens County64,126-1.61%
Knox County63,0733.24%
Union County59,91114.31%
Washington County59,541-3.51%
Lawrence County59,376-4.88%
Pickaway County58,7345.38%
Huron County58,588-1.63%
Sandusky County58,173-4.46%
Seneca County55,059-2.76%
Ashland County53,8651.02%
Darke County50,815-4.06%
Shelby County48,475-1.70%
Auglaize County45,830-0.22%
Logan County45,510-0.52%
Madison County45,1453.93%
Holmes County43,9023.36%
Brown County43,746-2.50%
Highland County43,308-0.71%
Fulton County42,298-0.78%
Clinton County42,2390.78%
Crawford County41,168-5.91%
Mercer County41,0570.66%
Ottawa County41,043-0.76%
Preble County40,763-3.34%
Guernsey County38,924-3.03%
Champaign County38,614-3.65%
Defiance County38,047-2.66%
Williams County36,920-1.57%
Coshocton County36,855-0.22%
Perry County36,1110.19%
Morrow County35,4501.89%
Putnam County33,632-2.45%
Jackson County32,382-2.62%
Hardin County31,628-1.54%
Gallia County29,651-4.58%
Fayette County28,688-1.13%
Van Wert County28,261-1.45%
Hocking County28,241-4.20%
Pike County27,747-3.47%
Adams County27,562-3.47%
Henry County26,932-4.39%
Carroll County26,561-7.92%
Meigs County23,156-2.43%
Wyandot County21,677-4.03%
Paulding County18,604-4.87%
Harrison County15,102-4.56%
Morgan County14,446-3.98%
Noble County14,240-2.87%
Monroe County13,470-7.79%
Vinton County13,215-1.42%