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. The population was 11,129 at the 2010 census. It is the principal city of the Cambridge Micropolitan Statistical Area and is located adjacent to the intersection of Interstates 70 and 77.Cambridge is well-known among glass collectors as being the location for the Cambridge Glass, Boyd Glass and Mosser Glass plants. The Cambridge area is also noted for its "S" shaped bridges, dating back to the building of the National Road in 1828.