Shihmen Dam (Chinese: 石門水壩; lit. 'Stone Gate Dam'; also spelled Shimen or Shihman) is a major rock fill dam across the Dahan River in northern Taoyuan City. It forms the Shihmen Reservoir (石門水庫), Taiwan's third largest reservoir or artificial lake. It provides irrigation in Taoyuan, flood control for the Taipei Basin, and hydroelectricity and domestic water supply for more than three million people in northern Taiwan.