Pasak Jolasid Dam, Thailand’s longest earthen dam, is an initiative of His Majesty King Bhumibol to mitigate flooding in Pasak River basin and the Chao Phraya River basin. It was built across Pasak River located at Nong Bua Sub-district, Phatthana Nikom District, Lopburi Province. The dam construction began on 2 December 1994 and was completed on 30 September 1999 under the responsibility of Department of Royal Irrigation.

On 25 November 1999, Their Majesties the King and Queen accompanied by Her Royal Highness Princess Maha Chakri Sirindhorn performed the opening ceremony of Pasak Jolasid Dam. Since then, the Dam has given benefits in many aspects to the people as the name bestowed by the King means “Efficient Diversion Dam”.