Kantharalak is a district (amphoe) in the southeastern part of Sisaket Province, northeastern Thailand. The old name of Kantharalak was Mueang Uthumphon Phisai, controlled by Mueang Khukhan. The central office was in Ban Kan Tuat, Tambon Uthumphon Phisai (not to be confused with latter-day Uthumphon Phisai District.) The present district office is in Tambon Nam Om. In 1939 the district name was changed from Nam Om to Kantharalak.
The name Kantharalak means 'countless ravines', from Pali kandara ('ravine') and the Sanskrit lakṣa, 'a hundred thousand'.
The district is defined in the south by the Dangrek Range. Neighbouring districts are (from the west clockwise): Khun Han, Si Rattana, and Benchalak of Sisaket Province; Thung Si Udom and Nam Khun of Ubon Ratchathani Province; Preah Vihear and Oddar Meancheay of Cambodia. The Khao Phra Wihan National Park office is in the district, while the main attraction of the park, the Khmer ruins of Prasat Preah Vihear, is across the border in Cambodia.

Source: https://en.wikipedia.org/wiki/Khukhan_District