Population of Counties in Ohio (2021)

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 2021 Population Growth Since 2010 Density (mi²)
Franklin County1,334,87014.46%2,919.97
Cuyahoga County1,221,780-4.41%2,672.59
Hamilton County821,5292.40%1,797.06
Summit County540,333-0.24%1,181.96
Montgomery County531,861-0.70%1,163.42
Lucas County425,820-3.54%931.46
Butler County385,4024.42%843.05
Stark County369,322-1.61%807.88
Lorain County311,3953.29%681.16
Warren County239,91612.41%524.81
Lake County230,2430.10%503.65
Mahoning County227,617-4.52%497.90
Delaware County217,34924.13%475.44
Clermont County208,2325.38%455.50
Trumbull County196,844-6.19%430.59
Medina County181,2825.09%396.55
Licking County179,2547.53%392.11
Greene County171,9196.39%376.07
Portage County162,3940.62%355.23
Fairfield County160,7589.79%351.65
Clark County133,193-3.67%291.35
Wood County131,5694.46%287.80
Richland County121,488-2.15%265.75
Wayne County115,5501.01%252.76
Miami County108,8776.23%238.16
Allen County101,603-4.47%222.25
Columbiana County100,703-6.66%220.28
Ashtabula County96,549-4.79%211.20
Geauga County93,057-0.36%203.56
Tuscarawas County91,803-0.80%200.82
Muskingum County86,3830.20%188.96
Ross County76,230-2.39%166.75
Hancock County75,5091.10%165.17
Scioto County74,982-5.88%164.02
Erie County73,772-4.16%161.37
Belmont County65,952-6.23%144.27
Athens County64,943-0.35%142.06
Jefferson County64,427-7.53%140.93
Marion County64,425-3.06%140.93
Knox County63,1663.40%138.17
Union County61,40017.03%134.31
Washington County59,511-3.57%130.18
Pickaway County59,2176.24%129.53
Lawrence County58,855-5.72%128.74
Sandusky County58,074-4.62%127.03
Huron County58,070-2.50%127.03
Seneca County55,146-2.60%120.63
Ashland County53,040-0.53%116.02
Darke County50,741-4.20%110.99
Shelby County48,526-1.67%106.15
Logan County46,3521.33%101.39
Auglaize County45,496-0.88%99.52
Madison County45,4154.56%99.34
Holmes County44,0423.69%96.34
Highland County43,379-0.55%94.89
Brown County43,156-3.80%94.40
Fulton County41,844-1.84%91.53
Clinton County41,734-0.45%91.29
Mercer County41,6122.02%91.02
Crawford County41,514-5.12%90.81
Preble County40,624-3.67%88.86
Ottawa County40,037-3.20%87.58
Champaign County39,085-2.48%85.50
Guernsey County38,603-3.87%84.44
Defiance County38,083-2.56%83.30
Coshocton County36,608-0.89%80.08
Williams County36,598-2.44%80.06
Perry County36,3240.80%79.46
Morrow County35,7582.78%78.22
Putnam County33,979-1.44%74.33
Jackson County32,507-2.23%71.11
Hardin County31,259-2.70%68.38
Gallia County29,804-4.08%65.20
Van Wert County28,319-1.25%61.95
Fayette County28,269-2.57%61.84
Hocking County28,078-4.75%61.42
Adams County27,706-2.91%60.61
Pike County27,452-4.05%60.05
Henry County26,836-4.74%58.70
Carroll County26,578-7.86%58.14
Meigs County22,593-4.80%49.42
Wyandot County21,480-4.91%46.99
Paulding County18,532-5.24%40.54
Harrison County14,786-6.57%32.34
Noble County14,578-0.56%31.89
Morgan County14,362-4.47%31.42
Monroe County13,388-8.36%29.29
Vinton County12,965-3.28%28.36