Franklin County is a county located in the U.S. state of Idaho. As of the 2020 Census the county had a population of 14,194. The county seat and largest city is Preston. The county was established in 1913 and named after Franklin D. Richards, an Apostle of the Church of Jesus Christ of Latter-day Saints. It is the only Franklin County in the United States that is not named after Benjamin Franklin. Franklin County is part of the Logan, UT-ID Metropolitan Statistical Area.

Preston is a city in Franklin County, Idaho, United States. The population was 5,591 at the 2020 census, up from 5,204 at the 2010 census. The city is the county seat of Franklin County. It is part of the Logan, Utah-Idaho Metropolitan Statistical Area.