The name Lak Si means the fowert milestane. The commonty here wis cried Lak Si acause o the fowert milestane o Khlong Prem Prachakhon (คลองเปรมประชากร) dug durin Keeng Chulalongkorn linkin Bangkok toward Bang Pa-In. Lak Si became a destrict on 21 November 1997, separatin frae Don Mueang destrict.