The highest summits of the Phanom Dong Rak Range, including Phu Khi Suk (753 m), Phu Khok Yai (693 m), Phu Chep Thong (692 m), Phu Tangok (689 m) and Chong Bok (603 m) are in this district, in the area where the borders of Thailand, Laos, and Cambodia intersect.