List of Ohio Counties and County Seats

The U.S. state of Ohio is divided into 88 counties. Explore list of California Counties and their County Seats in alphabetical order and check their population, areas and the date of formation.

S.N	County	County Seat	Population(2011)	Area	Formed
1	Adams County	West Union	28,550	583.91 sq mi	July 10, 1797
2	Allen County	Lima	106,331	404.43 sq mi	March 1, 1820
3	Ashland County	Ashland	53,139	424.37 sq mi	February 24, 1846
4	Ashtabula County	Jefferson	101,497	702.44 sq mi	June 7, 1807
5	Athens County	Athens	64,757	506.76 sq mi	March 1, 1805
6	Auglaize County	Wapakoneta	45,949	401.25 sq mi	February 14, 1848
7	Belmont County	St. Clairsville	70,400	537.35 sq mi	September 7, 1801
8	Brown County	Georgetown	44,846	491.76 sq mi	March 1, 1818
9	Butler County	Hamilton	368,130	467.27 sq mi	May 1, 1803
10	Carroll County	Carrollton	28,836	394.67 sq mi	January 1, 1833
11	Champaign County	Urbana	40,097	428.56 sq mi	March 1, 1805
12	Clark County	Springfield	138,333	399.86 sq mi	March 1, 1818
13	Clermont County	Batavia	197,363	451.99 sq mi	December 6, 1800
14	Clinton County	Wilmington	42,040	410.88 sq mi	March 1, 1810
15	Columbiana County	Lisbon	107,841	532.46 sq mi	May 1, 1803
16	Coshocton County	Coshocton	36,901	564.07 sq mi	January 31, 1810
17	Crawford County	Bucyrus	43,784	402.11 sq mi	April 1, 1820
18	Cuyahoga County	Cleveland	1,280,122	458.49 sq mi	June 7, 1807
19	Darke County	Greenville	52,959	599.80 sq mi	January 3, 1809
20	Defiance County	Defiance	39,037	411.16 sq mi	April 7, 1845
21	Delaware County	Delaware	174,214	442.41 sq mi	April 1, 1808
22	Erie County	Sandusky	77,079	254.88 sq mi	March 15, 1838
23	Fairfield County	Lancaster	146,156	505.11 sq mi	December 9, 1800
24	Fayette County	Washington Court House	29,030	406.58 sq mi	March 1, 1810
25	Franklin County	Columbus	1,163,414	539.87 sq mi	April 30, 1803
26	Fulton County	Wauseon	42,698	406.78 sq mi	April 1, 1850
27	Gallia County	Gallipolis	30,934	468.78 sq mi	April 30, 1803
28	Geauga County	Chardon	93,389	403.66 sq mi	March 1, 1806
29	Greene County	Xenia	161,573	414.88 sq mi	May 1, 1803
30	Guernsey County	Cambridge	40,087	521.90 sq mi	March 1, 1810
31	Hamilton County	Cincinnati	802,374	407.36 sq mi	January 2, 1790
32	Hancock County	Findlay	74,782	531.35 sq mi	April 1, 1820
33	Hardin County	Kenton	32,058	470.29 sq mi	April 1, 1820
34	Harrison County	Cadiz	15,864	403.53 sq mi	February 1, 1813
35	Henry County	Napoleon	28,215	416.50 sq mi	April 1, 1820
36	Highland County	Hillsboro	43,589	553.28 sq mi	May 1, 1805
37	Hocking County	Logan	29,380	422.75 sq mi	March 1, 1818
38	Holmes County	Millersburg	42,366	422.99 sq mi	January 20, 1824
39	Huron County	Norwalk	59,626	492.69 sq mi	March 7, 1809
40	Jackson County	Jackson	33,225	420.28 sq mi	March 1, 1816
41	Jefferson County	Steubenville	69,709	409.61 sq mi	July 29, 1797
42	Knox County	Mount Vernon	60,921	527.12 sq mi	March 1, 1808
43	Lake County	Painesville	230,041	228.21 sq mi	March 6, 1840
44	Lawrence County	Ironton	62,450	454.96 sq mi	December 21, 1815
45	Licking County	Newark	166,492	686.50 sq mi	March 1, 1808
46	Logan County	Bellefontaine	45,858	458.44 sq mi	March 1, 1818
47	Lorain County	Elyria	301,356	492.50 sq mi	December 26, 1822
48	Lucas County	Toledo	441,815	340.46 sq mi	June 20, 1835
49	Madison County	London	43,435	465.44 sq mi	March 1, 1810
50	Mahoning County	Youngstown	238,823	415.25 sq mi	March 1, 1846
51	Marion County	Marion	66,501	403.84 sq mi	April 1, 1820
52	Medina County	Medina	176,395	423 sq mi	February 18, 1812
53	Meigs County	Pomeroy	23,770	429.42 sq mi	April 1, 1819
54	Mercer County	Celina	40,814	463.27 sq mi	April 1, 1820
55	Miami County	Troy	102,506	407.04 sq mi	March 1, 1807
56	Monroe County	Woodsfield	14,642	455.54 sq mi	January 29, 1813
57	Montgomery County	Dayton	535,153	461.68 sq mi	May 1, 1803
58	Morgan County	McConnelsville	15,054	417.66 sq mi	December 29, 1817
59	Morrow County	Mount Gilead	34,827	406.22 sq mi	March 1, 1848
60	Muskingum County	Zanesville	86,074	664.63 sq mi	March 1, 1804[16][17]
61	Noble County	Caldwell	14,645	399.00 sq mi	April 1, 1851
62	Ottawa County	Port Clinton	41,428	254.95 sq mi	March 6, 1840
63	Paulding County	Paulding	19,614	416.26 sq mi	April 1, 1820
64	Perry County	New Lexington	36,058	409.78 sq mi	March 1, 1818
65	Pickaway County	Circleville	55,698	501.91 sq mi	March 1, 1810
66	Pike County	Waverly	28,709	441.49 sq mi	February 1, 1815
67	Portage County	Ravenna	161,419	492.39 sq mi	June 7, 1807
68	Preble County	Eaton	42,270	424.80 sq mi	March 1, 1808
69	Putnam County	Ottawa	34,499	483.87 sq mi	April 1, 1820
70	Richland County	Mansfield	124,475	496.88 sq mi	March 1, 1808
71	Ross County	Chillicothe	78,064	688.41 sq mi	August 20, 1798
72	Sandusky County	Fremont	60,944	409.18 sq mi	April 1, 1820
73	Scioto County	Portsmouth	79,499	612.27 sq mi	May 1, 1803
74	Seneca County	Tiffin	56,745	550.59 sq mi	April 1, 1820
75	Shelby County	Sidney	49,423	409.27 sq mi	April 1, 1819
76	Stark County	Canton	375,586	576.14 sq mi	February 13, 1808
77	Summit County	Akron	541,781	419.38 sq mi	March 3, 1840
78	Trumbull County	Warren	210,312	616.48 sq mi	July 10, 1800
79	Tuscarawas County	New Philadelphia	92,582	567.58 sq mi	March 15, 1808
80	Union County	Marysville	52,300	436.65 sq mi	April 1, 1820
81	Van Wert County	Van Wert	28,744	410.09 sq mi	April 1, 1820
82	Vinton County	McArthur	13,435	414.08 sq mi	March 23, 1850
83	Warren County	Lebanon	212,693	399.63 sq mi	May 1, 1803
84	Washington County	Marietta	61,778	635.15 sq mi	July 27, 1788
85	Wayne County	Wooster	114,520	555.36 sq mi	March 1, 1808
86	Williams County	Bryan	37,642	421.74 sq mi	April 1, 1820
87	Wood County	Bowling Green	125,488	617.32 sq mi	April 1, 1820
88	Wyandot County	Upper Sandusky	22,615	405.61 sq mi	February 3, 1845