Louisa County is a county located in the Commonwealth of Virginia. As of the 2020 census, the population was 37,596. The county seat is Louisa. Prior to colonial settlement, the area comprising Louisa County was occupied by several indigenous peoples including the Tutelo, the Monacan, and the Manahoac peoples, who eventually fled to join the …Louisa County is a county located in the Commonwealth of Virginia. As of the 2020 census, the population was 37,596. The county seat is Louisa. Prior to colonial settlement, the area comprising Louisa County was occupied by several indigenous peoples including the Tutelo, the Monacan, and the Manahoac peoples, who eventually fled to join the Cayuga Iroquois people in New York state under pressure from English settlers.