Most of the areas of Mae Hong Son Province are the complex mountain ranges of the Thai highlands, parts of which are still covered with rain forest. Of the approximately 6,976,650 rai of national forest reserves, it is estimated that 88.02% is pristine virgin forest.[citation needed]
The Daen Lao Range, in the northernmost portion of the province, marks the northern boundary between Thailand and Burma, while the Dawna Range in the west serves as the boundary between Thailand and Burma. The Thanon Thongchai Range in the east of the province serves as the boundary between the provinces of Mae Hong Son and Chiang Mai. The highest point of the province is Doi Mae Ya (ยอดเขาแม่ยะ), in the Pai District in the province's northeast, at 2,005 metres (6,578 ft) elevation.