In the early Showa period, Ogura-ike Pond was reclaimed, with a national route built from Kangetsu-kyo Bridge and over what used to be Ninomaru-ike Pond at Ogura-ike, and the road became a trunk route linking Kyoto and Nara cities. 
その後昭和初期に巨椋池が干拓され、観月橋から巨椋池の二の丸池であったところを国道が通され、京都と奈良の幹線道路の役割を担うようになった。