The county was formerly known as Queen's County () until its name was informally changed on establishment of the Irish Free State in 1922. The county's name was formerly spelt as "Laoighis" and "Leix". Despite the county's name being upheld as Laois through the 2001 Local Government Act, no legislation was ever enacted after independence explicitly changing the name from Queen's County, the name formally established under the 1898 Local Government Act which continued to have legal effect. When land is sold in the county the relevant title deeds are still updated as being in "Queen's County".