 When routes were first legislated in Pennsylvania in 1911, what would become PA 24 was designated as part of Legislative Route 216 between Red Lion and York and as part of Legislative Route 250 between York and New Cumberland.PA 24 was designated in 1928 to run from the Maryland border south of Stewartstown north to US 111 (Old York Road) in New Market.The route followed its current alignment to Red Lion before it ran northwest concurrent with PA 74 to York.