In 1867, the county was named for George Robertson, who was born in Kentucky in 1790 and died in 1874. He served in Congress from 1817 to 1821, where he sponsored the organization of the territory of Arkansas. He spent eight years in the Kentucky legislature, including six as Speaker, and promoted the common school system. He was a member of the Kentucky Court of Appeals from 1829 to 1834 and again from 1864 to 1871, and he was professor of law at Transylvania University from 1834 to 1857. The county was formed from parts of Bracken, Harrison, Mason, and Nicholas counties.