Robert P. Letcher, for whom the county was named in 1842, served as Governor of Kentucky from 1840 to 1844. Born in Virginia in 1788, he came to Kentucky in 1800. He served in the Kentucky Mounted Militia during the War of 1812, spent seven years in the legislature, including two years as Speaker of the House, and served in the U.S. Congress from 1823 to 1835. He was a presidential elector in 1836. During his term as governor he proclaimed the first Thanksgiving. He later served as minister to Mexico from 1849 to 1852. He died in 1861 and was buried in Frankfort Cemetery.