Ohio County Area & Size Rankings

Understanding Ohio’s county areas

The land-area range runs from Lake County at 229.4 mi² to Ashtabula County at 702.4 mi². The largest has 3.1 times the land area of the smallest and accounts for 1.7% of the combined county land in Ohio. Compare with every state’s largest county.

The median county-equivalent land area is 436 mi², below the national median of 604.5 mi². The median describes the middle of the county size distribution; it does not describe how people or development are distributed. A state with a few very large counties can have a much smaller median than its largest entry suggests.

Where water changes the picture

Cuyahoga County has the most assigned water area, at 788.3 mi². Lake County has the highest water share, with water making up 76.6% of its total area. Water area and water percentage answer different questions: the first measures an amount, while the second measures the mix of land and water.

Across all 88 entries, water accounts for 8.8% of the combined total area. This is calculated from the summed land and water measurements, rather than averaging county percentages, which would give each small and large county equal weight.

Where people live

An estimated 11,900,510 people lived in Ohio on July 1, 2025 (+0.9% since 2020), or 3.4% of the national total in this dataset. Franklin County is the most populous county equivalent, with 1,361,536 residents — 11.4% of the state. The largest by land, Ashtabula County, has 96,713.

Across the state there are 291 people per square mile of land. County densities range from 2,696 in Cuyahoga County to 29 in Monroe County; the median county equivalent has 120. Switch the map above to density to see where the state’s population concentrates.

Compare the largest and smallest county equivalents in Ohio to see land, water, and total area on the same scale.

These calculations use the 2026 Census county records listed below. County-equivalent boundaries vary between states; area alone does not measure population, density, or usable land. See coverage and calculation rules.

#	County / equivalent	Land	Water	Water share	Population	Per mi²
1	Ashtabula CountyGEOID 39007	702.4 mi²	665.8 mi²	48.7%	96,713	138
2	Ross CountyGEOID 39141	689.2 mi²	3.9 mi²	0.6%	76,429	111
3	Licking CountyGEOID 39089	682.4 mi²	4.9 mi²	0.7%	185,564	272
4	Muskingum CountyGEOID 39119	664.5 mi²	8 mi²	1.2%	87,014	131
5	Washington CountyGEOID 39167	632.3 mi²	8 mi²	1.2%	58,389	92
6	Trumbull CountyGEOID 39155	617.6 mi²	18.4 mi²	2.9%	198,972	322
7	Wood CountyGEOID 39173	617.2 mi²	3.4 mi²	0.5%	134,176	217
8	Scioto CountyGEOID 39145	610.2 mi²	6.2 mi²	1%	71,365	117
9	Darke CountyGEOID 39037	598.1 mi²	1.6 mi²	0.3%	51,520	86
10	Adams CountyGEOID 39001	583.9 mi²	2.4 mi²	0.4%	27,865	48
11	Stark CountyGEOID 39151	574.9 mi²	5.3 mi²	0.9%	373,771	650
12	Tuscarawas CountyGEOID 39157	567.6 mi²	4 mi²	0.7%	92,373	163
13	Coshocton CountyGEOID 39031	563.9 mi²	3.5 mi²	0.6%	37,188	66
14	Wayne CountyGEOID 39169	555 mi²	1.9 mi²	0.3%	116,758	210
15	Highland CountyGEOID 39071	553.1 mi²	4.7 mi²	0.8%	43,823	79
16	Seneca CountyGEOID 39147	551 mi²	1.8 mi²	0.3%	54,522	99
17	Franklin CountyGEOID 39049	532.4 mi²	11.2 mi²	2.1%	1,361,536	2,557
18	Belmont CountyGEOID 39013	532.2 mi²	9.1 mi²	1.7%	64,434	121
19	Columbiana CountyGEOID 39029	531.9 mi²	2.8 mi²	0.5%	99,377	187
20	Hancock CountyGEOID 39063	531.3 mi²	2.3 mi²	0.4%	75,034	141
21	Knox CountyGEOID 39083	525.5 mi²	4.1 mi²	0.8%	64,002	122
22	Guernsey CountyGEOID 39059	522.2 mi²	6 mi²	1.1%	38,379	73
23	Fairfield CountyGEOID 39045	504.4 mi²	4.2 mi²	0.8%	169,752	337
24	Athens CountyGEOID 39009	504.1 mi²	4.8 mi²	0.9%	63,197	125
25	Pickaway CountyGEOID 39129	501.3 mi²	5.3 mi²	1%	62,978	126
26	Richland CountyGEOID 39139	495.2 mi²	4.8 mi²	1%	124,893	252
27	Huron CountyGEOID 39077	492.2 mi²	3.3 mi²	0.7%	58,250	118
28	Lorain CountyGEOID 39093	490.5 mi²	432.2 mi²	46.8%	323,219	659
29	Brown CountyGEOID 39015	489.6 mi²	3.4 mi²	0.7%	44,397	91
30	Portage CountyGEOID 39133	487.5 mi²	16.6 mi²	3.3%	163,404	335
31	Putnam CountyGEOID 39137	482.5 mi²	1.8 mi²	0.4%	34,380	71
32	Hardin CountyGEOID 39065	470.3 mi²	0.2 mi²	0.1%	30,072	64
33	Madison CountyGEOID 39097	466.7 mi²	0.8 mi²	0.2%	46,985	101
34	Butler CountyGEOID 39017	466.5 mi²	3.5 mi²	0.8%	400,128	858
35	Gallia CountyGEOID 39053	466.5 mi²	4.7 mi²	1%	29,072	62
36	Mercer CountyGEOID 39107	462.4 mi²	11 mi²	2.3%	42,737	92
37	Montgomery CountyGEOID 39113	461.4 mi²	2.9 mi²	0.6%	539,598	1,170
38	Logan CountyGEOID 39091	458.5 mi²	8.3 mi²	1.8%	46,302	101
39	Cuyahoga CountyGEOID 39035	457.2 mi²	788.3 mi²	63.3%	1,232,925	2,696
40	Monroe CountyGEOID 39111	455.6 mi²	1.7 mi²	0.4%	12,994	29
41	Lawrence CountyGEOID 39087	453.4 mi²	3.9 mi²	0.8%	55,710	123
42	Clermont CountyGEOID 39025	452.6 mi²	7.7 mi²	1.7%	216,977	479
43	Delaware CountyGEOID 39041	443.1 mi²	14.2 mi²	3.1%	242,032	546
44	Pike CountyGEOID 39131	440.3 mi²	3.7 mi²	0.8%	27,061	61
45	Union CountyGEOID 39159	431.7 mi²	5.2 mi²	1.2%	73,446	170
46	Meigs CountyGEOID 39105	429.5 mi²	2.9 mi²	0.7%	21,587	50
47	Champaign CountyGEOID 39021	429 mi²	0.8 mi²	0.2%	38,820	90
48	Preble CountyGEOID 39135	424.2 mi²	2.3 mi²	0.5%	40,664	96
49	Ashland CountyGEOID 39005	423 mi²	3.8 mi²	0.9%	52,523	124
50	Holmes CountyGEOID 39075	422.6 mi²	1.4 mi²	0.3%	44,970	106
51	Medina CountyGEOID 39103	421.5 mi²	1.6 mi²	0.4%	185,025	439
52	Hocking CountyGEOID 39073	421.4 mi²	2.3 mi²	0.5%	27,512	65
53	Williams CountyGEOID 39171	420.7 mi²	2.4 mi²	0.6%	36,549	87
54	Jackson CountyGEOID 39079	420.3 mi²	1.2 mi²	0.3%	32,817	78
55	Paulding CountyGEOID 39125	416.4 mi²	2.4 mi²	0.6%	18,727	45
56	Morgan CountyGEOID 39115	416.4 mi²	5.4 mi²	1.3%	13,626	33
57	Henry CountyGEOID 39069	416 mi²	3.7 mi²	0.9%	27,598	66
58	Greene CountyGEOID 39057	413.6 mi²	2.6 mi²	0.6%	174,322	421
59	Summit CountyGEOID 39153	412.7 mi²	7.3 mi²	1.7%	538,376	1,305
60	Vinton CountyGEOID 39163	412.3 mi²	2.6 mi²	0.6%	12,645	31
61	Mahoning CountyGEOID 39099	411.5 mi²	13.7 mi²	3.2%	224,706	546
62	Defiance CountyGEOID 39039	411.4 mi²	2.7 mi²	0.7%	38,292	93
63	Van Wert CountyGEOID 39161	409.2 mi²	1.3 mi²	0.3%	29,013	71
64	Clinton CountyGEOID 39027	408.7 mi²	3.6 mi²	0.9%	42,301	103
65	Sandusky CountyGEOID 39143	408.2 mi²	9.5 mi²	2.3%	58,655	144
66	Jefferson CountyGEOID 39081	408.1 mi²	2.8 mi²	0.7%	63,597	156
67	Perry CountyGEOID 39127	407.9 mi²	4.5 mi²	1.1%	35,918	88
68	Shelby CountyGEOID 39149	407.7 mi²	3 mi²	0.7%	48,065	118
69	Wyandot CountyGEOID 39175	406.9 mi²	0.7 mi²	0.2%	21,567	53
70	Miami CountyGEOID 39109	406.6 mi²	3.1 mi²	0.7%	112,634	277
71	Fayette CountyGEOID 39047	406.4 mi²	0.7 mi²	0.2%	28,552	70
72	Morrow CountyGEOID 39117	406.1 mi²	1.1 mi²	0.3%	36,305	89
73	Hamilton CountyGEOID 39061	405.5 mi²	7.2 mi²	1.7%	838,418	2,068
74	Fulton CountyGEOID 39051	405.5 mi²	1.8 mi²	0.4%	41,853	103
75	Marion CountyGEOID 39101	403.8 mi²	0.4 mi²	0.1%	65,115	161
76	Allen CountyGEOID 39003	402.5 mi²	4.3 mi²	1.1%	100,881	251
77	Harrison CountyGEOID 39067	402.3 mi²	8.4 mi²	2.1%	14,070	35
78	Crawford CountyGEOID 39033	401.8 mi²	0.9 mi²	0.2%	41,896	104
79	Warren CountyGEOID 39165	401.4 mi²	6.1 mi²	1.5%	257,181	641
80	Auglaize CountyGEOID 39011	401.4 mi²	0.5 mi²	0.1%	45,909	114
81	Geauga CountyGEOID 39055	400.4 mi²	8 mi²	2%	95,676	239
82	Noble CountyGEOID 39121	398 mi²	6.6 mi²	1.6%	14,276	36
83	Clark CountyGEOID 39023	395.9 mi²	5.6 mi²	1.4%	135,340	342
84	Carroll CountyGEOID 39019	394.7 mi²	4.3 mi²	1.1%	26,475	67
85	Lucas CountyGEOID 39095	339.7 mi²	256.2 mi²	43%	423,347	1,246
86	Ottawa CountyGEOID 39123	254.7 mi²	330.4 mi²	56.5%	39,481	155
87	Erie CountyGEOID 39043	251.3 mi²	374.5 mi²	59.8%	73,296	292
88	Lake CountyGEOID 39085	229.4 mi²	749.9 mi²	76.6%	232,217	1,012

County / equivalent

Land

Water

Water share

Population

Per mi²

Ashtabula CountyGEOID 39007

702.4 mi²

665.8 mi²

48.7%

96,713

138

Ross CountyGEOID 39141

689.2 mi²

3.9 mi²

0.6%

76,429

111

Licking CountyGEOID 39089

682.4 mi²

4.9 mi²

0.7%

185,564

272

Muskingum CountyGEOID 39119

664.5 mi²

8 mi²

1.2%

87,014

131

Washington CountyGEOID 39167

632.3 mi²

8 mi²

1.2%

58,389

Trumbull CountyGEOID 39155

617.6 mi²

18.4 mi²

2.9%

198,972

322

Wood CountyGEOID 39173

617.2 mi²

3.4 mi²

0.5%

134,176

217

Scioto CountyGEOID 39145

610.2 mi²

6.2 mi²

71,365

117

Darke CountyGEOID 39037

598.1 mi²

1.6 mi²

0.3%

51,520

Adams CountyGEOID 39001

583.9 mi²

2.4 mi²

0.4%

27,865

Stark CountyGEOID 39151

574.9 mi²

5.3 mi²

0.9%

373,771

650

Tuscarawas CountyGEOID 39157

567.6 mi²

4 mi²

0.7%

92,373

163

Coshocton CountyGEOID 39031

563.9 mi²

3.5 mi²

0.6%

37,188

Wayne CountyGEOID 39169

555 mi²

1.9 mi²

0.3%

116,758

210

Highland CountyGEOID 39071

553.1 mi²

4.7 mi²

0.8%

43,823

Seneca CountyGEOID 39147

551 mi²

1.8 mi²

0.3%

54,522

Franklin CountyGEOID 39049

532.4 mi²

11.2 mi²

2.1%

1,361,536

2,557

Belmont CountyGEOID 39013

532.2 mi²

9.1 mi²

1.7%

64,434

121

Columbiana CountyGEOID 39029

531.9 mi²

2.8 mi²

0.5%

99,377

187

Hancock CountyGEOID 39063

531.3 mi²

2.3 mi²

0.4%

75,034

141

Knox CountyGEOID 39083

525.5 mi²

4.1 mi²

0.8%

64,002

122

Guernsey CountyGEOID 39059

522.2 mi²

6 mi²

1.1%

38,379

Fairfield CountyGEOID 39045

504.4 mi²

4.2 mi²

0.8%

169,752

337

Athens CountyGEOID 39009

504.1 mi²

4.8 mi²

0.9%

63,197

125

Pickaway CountyGEOID 39129

501.3 mi²

5.3 mi²

62,978

126

Richland CountyGEOID 39139

495.2 mi²

4.8 mi²

124,893

252

Huron CountyGEOID 39077

492.2 mi²

3.3 mi²

0.7%

58,250

118

Lorain CountyGEOID 39093

490.5 mi²

432.2 mi²

46.8%

323,219

659

Brown CountyGEOID 39015

489.6 mi²

3.4 mi²

0.7%

44,397

Portage CountyGEOID 39133

487.5 mi²

16.6 mi²

3.3%

163,404

335

Putnam CountyGEOID 39137

482.5 mi²

1.8 mi²

0.4%

34,380

Hardin CountyGEOID 39065

470.3 mi²

0.2 mi²

0.1%

30,072

Madison CountyGEOID 39097

466.7 mi²

0.8 mi²

0.2%

46,985

101

Butler CountyGEOID 39017

466.5 mi²

3.5 mi²

0.8%

400,128

858

Gallia CountyGEOID 39053

466.5 mi²

4.7 mi²

29,072

Mercer CountyGEOID 39107

462.4 mi²

11 mi²

2.3%

42,737

Montgomery CountyGEOID 39113

461.4 mi²

2.9 mi²

0.6%

539,598

1,170

Logan CountyGEOID 39091

458.5 mi²

8.3 mi²

1.8%

46,302

101

Cuyahoga CountyGEOID 39035

457.2 mi²

788.3 mi²

63.3%

1,232,925

2,696

Monroe CountyGEOID 39111

455.6 mi²

1.7 mi²

0.4%

12,994

Lawrence CountyGEOID 39087

453.4 mi²

3.9 mi²

0.8%

55,710

123

Clermont CountyGEOID 39025

452.6 mi²

7.7 mi²

1.7%

216,977

479

Delaware CountyGEOID 39041

443.1 mi²

14.2 mi²

3.1%

242,032

546

Pike CountyGEOID 39131

440.3 mi²

3.7 mi²

0.8%

27,061

Union CountyGEOID 39159

431.7 mi²

5.2 mi²

1.2%

73,446

170

Meigs CountyGEOID 39105

429.5 mi²

2.9 mi²

0.7%

21,587

Champaign CountyGEOID 39021

429 mi²

0.8 mi²

0.2%

38,820

Preble CountyGEOID 39135

424.2 mi²

2.3 mi²

0.5%

40,664

Ashland CountyGEOID 39005

423 mi²

3.8 mi²

0.9%

52,523

124

Holmes CountyGEOID 39075

422.6 mi²

1.4 mi²

0.3%

44,970

106

Medina CountyGEOID 39103

421.5 mi²

1.6 mi²

0.4%

185,025

439

Hocking CountyGEOID 39073

421.4 mi²

2.3 mi²

0.5%

27,512

Williams CountyGEOID 39171

420.7 mi²

2.4 mi²

0.6%

36,549

Jackson CountyGEOID 39079

420.3 mi²

1.2 mi²

0.3%

32,817

Paulding CountyGEOID 39125

416.4 mi²

2.4 mi²

0.6%

18,727

Morgan CountyGEOID 39115

416.4 mi²

5.4 mi²

1.3%

13,626

Henry CountyGEOID 39069

416 mi²

3.7 mi²

0.9%

27,598

Greene CountyGEOID 39057

413.6 mi²

2.6 mi²

0.6%

174,322

421

Summit CountyGEOID 39153

412.7 mi²

7.3 mi²

1.7%

538,376

1,305

Vinton CountyGEOID 39163

412.3 mi²

2.6 mi²

0.6%

12,645

Mahoning CountyGEOID 39099

411.5 mi²

13.7 mi²

3.2%

224,706

546

Defiance CountyGEOID 39039

411.4 mi²

2.7 mi²

0.7%

38,292

Van Wert CountyGEOID 39161

409.2 mi²

1.3 mi²

0.3%

29,013

Clinton CountyGEOID 39027

408.7 mi²

3.6 mi²

0.9%

42,301

103

Sandusky CountyGEOID 39143

408.2 mi²

9.5 mi²

2.3%

58,655

144

Jefferson CountyGEOID 39081

408.1 mi²

2.8 mi²

0.7%

63,597

156

Perry CountyGEOID 39127

407.9 mi²

4.5 mi²

1.1%

35,918

Shelby CountyGEOID 39149

407.7 mi²

3 mi²

0.7%

48,065

118

Wyandot CountyGEOID 39175

406.9 mi²

0.7 mi²

0.2%

21,567

Miami CountyGEOID 39109

406.6 mi²

3.1 mi²

0.7%

112,634

277

Fayette CountyGEOID 39047

406.4 mi²

0.7 mi²

0.2%

28,552

Morrow CountyGEOID 39117

406.1 mi²

1.1 mi²

0.3%

36,305

Hamilton CountyGEOID 39061

405.5 mi²

7.2 mi²

1.7%

838,418

2,068

Fulton CountyGEOID 39051

405.5 mi²

1.8 mi²

0.4%

41,853

103

Marion CountyGEOID 39101

403.8 mi²

0.4 mi²

0.1%

65,115

161

Allen CountyGEOID 39003

402.5 mi²

4.3 mi²

1.1%

100,881

251

Harrison CountyGEOID 39067

402.3 mi²

8.4 mi²

2.1%

14,070

Crawford CountyGEOID 39033

401.8 mi²

0.9 mi²

0.2%

41,896

104

Warren CountyGEOID 39165

401.4 mi²

6.1 mi²

1.5%

257,181

641

Auglaize CountyGEOID 39011

401.4 mi²

0.5 mi²

0.1%

45,909

114

Geauga CountyGEOID 39055

400.4 mi²

8 mi²

95,676

239

Noble CountyGEOID 39121

398 mi²

6.6 mi²

1.6%

14,276

Clark CountyGEOID 39023

395.9 mi²

5.6 mi²

1.4%

135,340

342

Carroll CountyGEOID 39019

394.7 mi²

4.3 mi²

1.1%

26,475

Lucas CountyGEOID 39095

339.7 mi²

256.2 mi²

43%

423,347

1,246

Ottawa CountyGEOID 39123

254.7 mi²

330.4 mi²

56.5%

39,481

155

Erie CountyGEOID 39043

251.3 mi²

374.5 mi²

59.8%

73,296

292

Lake CountyGEOID 39085

229.4 mi²

749.9 mi²

76.6%

232,217

1,012

Ohio counties by area

Understanding Ohio’s county areas

Where water changes the picture

Where people live

Complete area table