Doksan Fortress (Korean: 독산성; Hanja: 禿山城) is a Korean hill fort located in Osan, South Korea. It is notable for the Siege of Doksan in 1593, during which the Japanese forces failed to defeat Gwon Yul in the Imjin War. Within the fort, there are significant landmarks such as the Bujek Buddhist Temple and Semadae, a monument commemorating Gwon Yul's victory. The site is designated as a Historic Site of South Korea. Each September, the annual Doksanseong Culture and Art Festival takes place near the fort.