Cambridge is a city in and the county seat of Guernsey County, Ohio, United States. It lies in southeastern Ohio, in the Appalachian Plateau of the Appalachian Mountains about 75 miles east of Columbus and approximately 124 miles south of Cleveland. The population was 10,089 at the 2020 census. It is the principal city of the Cambridge micropolitan area and is located adjacent to the intersection of Interstates 70 and 77.