Noble County is a county located in the U.S. state of Ohio. As of the 2020 census, the population was 14,115, making it the fourth-least populous county in Ohio. Its county seat is Caldwell. The county is named for Rep. Warren P. Noble of the Ohio House of Representatives, who was an early settler there.

Guernsey County is a county located in the U.S. state of Ohio. As of the 2020 census, the population was 38,438. Its county seat and largest city is Cambridge. It is named for the Isle of Guernsey in the English Channel, from which many of the county's early settlers emigrated.