 According to the historian Prince Damrong Rajanubhab, "Mueang" Lom Sak was established in the reign of King Nangklao (Rama III).When King Chulalongkorn (Rama V) created the monthon as part of the "Thesaphiban" administrative reforms, "Mueang" Lom Sak was controlled by Monthon Phetchabun.Later it was downgraded to be a district of Phetchabun Province.