Louisa is a home rule-class city located at the merger of the Levisa and Tug Forks into the Big Sandy River. It is located in Lawrence County, Kentucky, in the United States, and is the seat of its county. The population was 2,467 at the 2010 census and an estimated 2,375 in 2018.
The origin of the city's name is unclear. Theories include that it was named for Louisa County, Virginia, or a corruption of the name of the Levisa, or that it was named after Louisa Swetnam, one of the first white children born in the area. The Levisa Fork was originally written and spoken as the "Louisa Fork", which is the likely origin of the name. It is also possible that the town name was connected to the Spanish Era in Kentucky. Spain made land grants in what is now Kentucky. Explorer Dr. Thomas Walker named the river after a family member. Others claim that the Levisa Fork is named for Levite connections to the Cherokee and other native tribes prior to later European contact.