National Route 1 () is a national highway in South Korea. It connects Mokpo, South Jeolla Province with the city of Paju in Gyeonggi-do. Before the division of the Korean peninsula, the highway ran until Sinuiju, North Pyongan Province, in present-day North Korea.
Parts of National Route 1 were already being used as major roads during the Joseon dynasty. The portion from Seoul to Suwon aligns with Siheung Road and Gyeongsu Road which were established during the time of King Jeongjo, and the portion from Seoul to Euiju aligns with a major road used by envoys to and from China which was thus maintained by the government.
During the Japanese occupation, the Japanese government laid a new road that originates from Mokpo that passes through Seoul and ends at Sinuiju. The portion from Mokpo to Seoul was named National Route 3, and the portion from Seoul to Sinuiju was named National Route 2. The new road mostly used roads that were already established during the Joseon dynasty, but some parts were newly established as the Japanese government preferred a straighter route than one that passed through as many settlements along the way. The Japanese government then used the new route to invade Manchuria and expropriate rice to back to Japan.
After the Korean War, the route was separated at Imjingak. The route was expanded to four lanes from Daejeon to Sejong in 1999, and from Nonsan to Daejeon in 2004. The route was also connected to the Kaesong Industrial Region in 2000. In 2010, the route was straightened and no longer directly passed through Jeonju. As Sejong City developed, the city's portion of the route was expanded to 6-8 lanes.
On June 29, 2012, Mokpo Bridge was opened, and the route's starting point moved 4.27 km further south.
IS: Intersection, IC: Interchange