The old name of Kantharalak was MueangUthumphon Phisai, controlled by Mueang Khukhan. The central office was located Ban Kan Tuat, Tambon Uthumphon Phisai (not to be confused with later-day Uthumphon Phisai District.) The present office district is located at Tambon Nam Om.
In 1939 the district was renamed from Nam Om to Kantharalak.
Neighboring districts are (from the west clockwise) Khun Han, Si Rattana, Benchalakof Sisaket Province, Thung Si Udom, Nam Khun of Ubon Ratchathani Province, Preah Vihear and Oddar Meancheay of Cambodia.
The Khao Phra Wihan National Park office is located in the district, while the main attraction of the park - the Khmer ruins ofPrasat Preah Vihear - is located across the boundary in Cambodia.