Most people will be familiar with our sister island’s namesake in the US – New Jersey, but less well known is that there’s also a Guernsey in the US , or to be precise a Guernsey County in Ohio. Guernsey County is almost as old as the United States itself. It was formed on the 10th March 1810 when the US was only 24 years old. The County is located in the State of Ohio and rests in the foothills of the Appalachian Mountains.