Tanao Si Mountain Range

Tenasserim Hills
တနင်္သာရီ တောင်တန်း (တနသၤာရီေတာင္တန္း) ทิวเขาตะนาวศรี Banjaran Tanah Seri
View from the Death Railway over the Kwai River, Kanchanaburi Province
Highest point
Peak	Mount Tahan (Malaysia)
Elevation	2,187 m (7,175 ft)
Coordinates	4°38′00″N 102°14′00″E / 4.63333°N 102.23333°E / 4.63333; 102.23333Coordinates: 4°38′00″N 102°14′00″E / 4.63333°N 102.23333°E / 4.63333; 102.23333
Dimensions
Length	1,670 km (1,040 mi) N/S
Width	130 km (81 mi) E/W
Geography
Extent of the Tenasserim Hills and their subranges
Countries	Myanmar, Thailand and Malaysia
Parent range	Indo-Malayan System
Geology
Age of rock	Permian, Triassic
Type of rock	Granite and Limestone

Tenasserim Hills or Tenasserim Range (Burmese: တနင်္သာရီ တောင်တန်း, [tənɪ̀ɴθàjì tàʊɴdáɴ]; Thai: ทิวเขาตะนาวศรี, rtgs: Thio Khao Tanao Si, pronounced [tʰīw kʰǎw tā.nāːw sǐː]; Malay: Banjaran Tenasserim) is the geographical name of a roughly 1,700 km long mountain chain, part of the Indo-Malayan mountain system in Southeast Asia.

Despite their relatively scant altitude these mountains form an effective barrier between Thailand and Burma in their northern and central region. There are only two main transnational roads and cross-border points between Chumphon and Tak, at the Three Pagodas Pass and at Mae Sot. The latter is located beyond the northern end of the range, where the Tenasserim Hills meet the Dawna Range. Minor cross-border points are Sing Khon, near Prachuap Khiri Khan, as well as Bong Ti and Phu Nam Ron west of Kanchanaburi. The latter is expected to gain in importance if the planned Dawei deepwater port project goes ahead, along with a highway and a railway line between Bangkok and that harbor.