Ohio county geography overview
Ohio has 88 counties, which places it 13th among the 50 state and District of Columbia maps in this atlas when ordered by number of county-level units. Their combined 40,858.7 square miles of land place the state 35th by mapped land area.
The average county-level area is 464 square miles, while the median is 436 square miles. The median is often the better description of a typical unit because one or two very large areas can pull the average upward. The five largest units together account for about 8% of the state’s mapped land area.
Largest and smallest Ohio counties
Ashtabula County is the largest county-level unit by land area at 702.4 square miles. It represents about 2% of all mapped land in Ohio. At the other end of the range, Lake County has 229.4 square miles of land.
Largest by land area
- Ashtabula County702.4 sq mi
- Ross County689.2 sq mi
- Licking County682.4 sq mi
- Muskingum County664.5 sq mi
- Washington County632.2 sq mi
Smallest by land area
- Lake County229.4 sq mi
- Erie County251.3 sq mi
- Ottawa County254.7 sq mi
- Lucas County339.7 sq mi
- Carroll County394.7 sq mi
Rankings use land area rather than total area. This avoids making coastal or lake counties appear larger solely because their boundaries include extensive water.
Alphabetical list of Ohio counties
The table is alphabetical, so it works as a name and FIPS-code reference rather than an area ranking. Every identifier begins with the Ohio state FIPS prefix 39. Land and water figures are rounded to one decimal place.
88 county-level areas
Download county data / numbered map key (CSV)| No. | Name | FIPS code | Land area | Water area |
|---|---|---|---|---|
| 1 | Adams County | 39001 | 583.9 sq mi | 2.4 sq mi |
| 2 | Allen County | 39003 | 402.5 sq mi | 4.3 sq mi |
| 3 | Ashland County | 39005 | 423 sq mi | 3.8 sq mi |
| 4 | Ashtabula County | 39007 | 702.4 sq mi | 665.8 sq mi |
| 5 | Athens County | 39009 | 503.6 sq mi | 4.8 sq mi |
| 6 | Auglaize County | 39011 | 401.4 sq mi | 0.5 sq mi |
| 7 | Belmont County | 39013 | 532.2 sq mi | 9.1 sq mi |
| 8 | Brown County | 39015 | 489.6 sq mi | 3.4 sq mi |
| 9 | Butler County | 39017 | 466.5 sq mi | 3.5 sq mi |
| 10 | Carroll County | 39019 | 394.7 sq mi | 4.3 sq mi |
| 11 | Champaign County | 39021 | 429 sq mi | 0.8 sq mi |
| 12 | Clark County | 39023 | 395.9 sq mi | 5.6 sq mi |
| 13 | Clermont County | 39025 | 452.6 sq mi | 7.7 sq mi |
| 14 | Clinton County | 39027 | 408.7 sq mi | 3.6 sq mi |
| 15 | Columbiana County | 39029 | 531.9 sq mi | 2.8 sq mi |
| 16 | Coshocton County | 39031 | 563.9 sq mi | 3.5 sq mi |
| 17 | Crawford County | 39033 | 401.8 sq mi | 0.9 sq mi |
| 18 | Cuyahoga County | 39035 | 457.2 sq mi | 788.3 sq mi |
| 19 | Darke County | 39037 | 598.1 sq mi | 1.6 sq mi |
| 20 | Defiance County | 39039 | 411.4 sq mi | 2.7 sq mi |
| 21 | Delaware County | 39041 | 443.1 sq mi | 14.2 sq mi |
| 22 | Erie County | 39043 | 251.3 sq mi | 374.5 sq mi |
| 23 | Fairfield County | 39045 | 504.4 sq mi | 4.2 sq mi |
| 24 | Fayette County | 39047 | 406.4 sq mi | 0.7 sq mi |
| 25 | Franklin County | 39049 | 532.4 sq mi | 11.2 sq mi |
| 26 | Fulton County | 39051 | 405.4 sq mi | 1.8 sq mi |
| 27 | Gallia County | 39053 | 466.5 sq mi | 4.7 sq mi |
| 28 | Geauga County | 39055 | 400.4 sq mi | 8 sq mi |
| 29 | Greene County | 39057 | 413.6 sq mi | 2.6 sq mi |
| 30 | Guernsey County | 39059 | 522.2 sq mi | 6 sq mi |
| 31 | Hamilton County | 39061 | 405.5 sq mi | 7.2 sq mi |
| 32 | Hancock County | 39063 | 531.3 sq mi | 2.3 sq mi |
| 33 | Hardin County | 39065 | 470.3 sq mi | 0.2 sq mi |
| 34 | Harrison County | 39067 | 402.3 sq mi | 8.4 sq mi |
| 35 | Henry County | 39069 | 416 sq mi | 3.7 sq mi |
| 36 | Highland County | 39071 | 553.1 sq mi | 4.7 sq mi |
| 37 | Hocking County | 39073 | 421.3 sq mi | 2.3 sq mi |
| 38 | Holmes County | 39075 | 422.6 sq mi | 1.4 sq mi |
| 39 | Huron County | 39077 | 492.2 sq mi | 3.3 sq mi |
| 40 | Jackson County | 39079 | 420.3 sq mi | 1.2 sq mi |
| 41 | Jefferson County | 39081 | 408.1 sq mi | 2.8 sq mi |
| 42 | Knox County | 39083 | 525.5 sq mi | 4.1 sq mi |
| 43 | Lake County | 39085 | 229.4 sq mi | 749.9 sq mi |
| 44 | Lawrence County | 39087 | 453.4 sq mi | 3.9 sq mi |
| 45 | Licking County | 39089 | 682.4 sq mi | 4.9 sq mi |
| 46 | Logan County | 39091 | 458.5 sq mi | 8.3 sq mi |
| 47 | Lorain County | 39093 | 490.5 sq mi | 432.2 sq mi |
| 48 | Lucas County | 39095 | 339.7 sq mi | 256.2 sq mi |
| 49 | Madison County | 39097 | 466.7 sq mi | 0.8 sq mi |
| 50 | Mahoning County | 39099 | 411.5 sq mi | 13.7 sq mi |
| 51 | Marion County | 39101 | 403.8 sq mi | 0.4 sq mi |
| 52 | Medina County | 39103 | 421.5 sq mi | 1.6 sq mi |
| 53 | Meigs County | 39105 | 430.1 sq mi | 2.9 sq mi |
| 54 | Mercer County | 39107 | 462.4 sq mi | 11 sq mi |
| 55 | Miami County | 39109 | 406.6 sq mi | 3.1 sq mi |
| 56 | Monroe County | 39111 | 455.6 sq mi | 1.7 sq mi |
| 57 | Montgomery County | 39113 | 461.4 sq mi | 2.9 sq mi |
| 58 | Morgan County | 39115 | 416.4 sq mi | 5.4 sq mi |
| 59 | Morrow County | 39117 | 406.1 sq mi | 1.1 sq mi |
| 60 | Muskingum County | 39119 | 664.5 sq mi | 8 sq mi |
| 61 | Noble County | 39121 | 398 sq mi | 6.6 sq mi |
| 62 | Ottawa County | 39123 | 254.7 sq mi | 330.4 sq mi |
| 63 | Paulding County | 39125 | 416.4 sq mi | 2.4 sq mi |
| 64 | Perry County | 39127 | 407.9 sq mi | 4.5 sq mi |
| 65 | Pickaway County | 39129 | 501.3 sq mi | 5.3 sq mi |
| 66 | Pike County | 39131 | 440.3 sq mi | 3.7 sq mi |
| 67 | Portage County | 39133 | 487.5 sq mi | 16.6 sq mi |
| 68 | Preble County | 39135 | 424.2 sq mi | 2.3 sq mi |
| 69 | Putnam County | 39137 | 482.5 sq mi | 1.8 sq mi |
| 70 | Richland County | 39139 | 495.2 sq mi | 4.8 sq mi |
| 71 | Ross County | 39141 | 689.2 sq mi | 3.9 sq mi |
| 72 | Sandusky County | 39143 | 408.2 sq mi | 9.5 sq mi |
| 73 | Scioto County | 39145 | 610.2 sq mi | 6.2 sq mi |
| 74 | Seneca County | 39147 | 551 sq mi | 1.8 sq mi |
| 75 | Shelby County | 39149 | 407.7 sq mi | 3 sq mi |
| 76 | Stark County | 39151 | 574.9 sq mi | 5.3 sq mi |
| 77 | Summit County | 39153 | 412.7 sq mi | 7.3 sq mi |
| 78 | Trumbull County | 39155 | 617.6 sq mi | 18.4 sq mi |
| 79 | Tuscarawas County | 39157 | 567.6 sq mi | 4 sq mi |
| 80 | Union County | 39159 | 431.7 sq mi | 5.2 sq mi |
| 81 | Van Wert County | 39161 | 409.1 sq mi | 1.3 sq mi |
| 82 | Vinton County | 39163 | 412.4 sq mi | 2.6 sq mi |
| 83 | Warren County | 39165 | 401.4 sq mi | 6.1 sq mi |
| 84 | Washington County | 39167 | 632.2 sq mi | 8 sq mi |
| 85 | Wayne County | 39169 | 555 sq mi | 1.9 sq mi |
| 86 | Williams County | 39171 | 420.7 sq mi | 2.4 sq mi |
| 87 | Wood County | 39173 | 617.2 sq mi | 3.4 sq mi |
| 88 | Wyandot County | 39175 | 406.9 sq mi | 0.7 sq mi |
How to read and use this map
County lines are administrative boundaries, not postal routes. A mailing address can use a city name associated with a neighboring area, and ZIP codes can cross county lines. When you need to identify a county for an address, confirm it with an official geocoder or local government source.
For classroom or planning use, download a PDF from the controls above. Labelled exports use numbered callouts for crowded areas; numbered quiz maps match the alphabetical county list. SVG files keep the boundary lines sharp at larger paper sizes.
Frequently asked questions
How many counties are in Ohio?
Ohio has 88 counties in the U.S. Census Bureau’s 2025 cartographic boundary file.
Can I print this Ohio county map?
Yes. Choose Download / print and select PDF for a landscape Letter page, PNG for an image, or SVG for editable vector artwork. Because the map is SVG, its boundary lines stay sharp when scaled.
What is the largest county in Ohio?
Ashtabula County is the largest by land area in this dataset at 702.4 square miles. This is an area ranking, not a population ranking.
What is the smallest county in Ohio?
Lake County is the smallest by land area in this dataset at 229.4 square miles.
Are these legal survey boundaries?
No. This is a generalized reference map. Property, parcel, election, and legal boundary questions should be checked with the relevant state or local agency.
Map source
U.S. Census Bureau, 2025 Cartographic Boundary File, Counties, 1:5,000,000. Land and water area fields are supplied in the same file and converted from square meters to square miles. Accessed September 27, 2026.