Placed at the summit of Hoamsan Mountain (San 93-2 Siheung-dong, Geumcheon-gu), Hanumul Well was also called Cheonjeong (天井; Heaven's Well), Yongbok (Dragon's Den), or Yongchu (Dragon's Well). It was built during the Unified Silla Period (6th-7th century), and was rebuilt during the Joseon Dynasty after being relocated slightly to the west. Its dimensions during the Unified Silla Period were 17.8m from east to west, 13.6m from north to south, and 2.5m in depth, while the well built during the Joseon Dynasty was 22m from east to west, 12m from north to south, and 1.2m in depth.

During the Japanese invasion of Korea, General Sun Geo-yi along with General Kwon Yul at Haengjusanseong Fortress used this well as the water source for their troops, and rituals for rain were held by the well during droughts. Meanwhile, some argue that this place was built to fight fire in connection with the founding myth of the Joseon Dynasty.