List of counties in Ohio



There are 88 counties in the U.S. state of Ohio. Nine of them existed at the time of the Ohio Constitutional Convention in 1802. A tenth county, Wayne, was established on August 15, 1796, and encompassed roughly the present state of Michigan. During the Convention, the county was opposed to statehood, and was not only left out of the Convention, but dissolved; the current Wayne County is in northeastern Ohio, considerably distant from the area that was the original Wayne County.

The Ohio Constitution allows counties to set up a charter government as many cities and villages do, but only Summit and Cuyahoga counties have done so, the latter having been approved by voters in November 2009. Counties do not possess home rule powers and can do only what has been expressly authorized by the Ohio General Assembly. The elected county officials in Ohio county governments include three commissioners, a sheriff (the highest law enforcement officer in the county); prosecutor (equivalent of a district attorney in other states); coroner, engineer, Recorder, auditor, treasurer, and clerk of courts.

Population figures are based on the 2023 vintage Census population estimates. The population of Ohio was 11,785,935 at that time, a decrease of 0.1% from 2020. The average population of Ohio's counties was 133,931; Franklin County was the most populous (1,326,063) and Vinton County was the least (12,474). The average land area is 464 sqmi. The largest county by area is Ashtabula County at 702.44 sqmi, and its neighbor, Lake County, is the smallest at 228.21 sqmi. The total area of the state is 40,860.69 sqmi.

List of counties

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List of county codes
The Federal Information Processing Standard (FIPS) is used by the U.S. government to uniquely identify counties. In the following table, these codes link to the United States Census Bureau's "quick facts" for each county. Ohio's FIPS code of 39 is used to distinguish from counties in other states. For example, Adams County's unique nationwide identifier is 39001.

Various state agencies identify counties by different coding schemes. The Ohio Department of Taxation assigns consecutive numbers for the purpose of enumerating taxing districts. The Ohio Department of Public Safety, including the Ohio Bureau of Motor Vehicles, associates these county numbers with vehicle registrations. The Department of Transportation uses three-letter abbreviations in road inventory and traffic management applications. For historic preservation purposes, Ohio History Connection refers to counties by two- and three-letter abbreviations in the Ohio Archaeological Inventory and Ohio Historic Inventory, respectively.