The most important are Quelpart and the Nan Hau group. The latter, 36 m.
Longitude, which culminates in the Altyn Tagh, and extends eastwards in a continuous water-divide to the Nan Shan mountains, north of the Koko Nor basin.
These five provinces, however, do not include the elevated steppes of Tsaidam (extending between the Kuen-lun and the Altyn Tagh or Nan Shan ranges), inhabited by a mixed race of marauding people, Tunguts and Mongols.
Leaving the west gate of the city two roads lead to Lan-chow Fu, from which town begins the great high road into Central Asia by way of Lian-chow Fu, Kan-chow Fu and Su-chow to Hami, where it forks into two branches which follow respectively the northern and southern foot of the Tian-shan range, and are known as the Tian-shan pei lu and the Tian-shan nan lu.
The more important places of northern Siam include Chieng Mai, the capital of the north, Chieng Rai, near the northern frontier; Lampun, also known as Labong (originally Haribunchai), the first Lao settlement in Siam; Lampang, Tern, Nan and Pre, each the seat of a Lao chief and of a Siamese commissioner; Utaradit, Pichai, Pichit, Pechabun and Raheng, the last of importance as a timber station, with Phitsnulok, Sukhotai, Swankalok, Kampeng Pet and Nakhon Sawan, former capitals of Khmer-Siamese kingdoms, and at present the headquarters of provincial governments.
It was along these roads that the fame of China first reached Europe, and it was by the Tian-shan nan lu that Marco Polo entered the empire.