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.