Chiang Mai valley averages 310 metres (1,027 feet) above sea level, and the province covers 20,107 square kilometres (12,566,910 rai). The widest point of the province measures 136 kilometres (85 miles), and the longest 320 kilometres (200 miles).
To the north, a 227 kilometre (141.88 miles) stretch of mountains divides Chiang Mai's northern districts of Fang and Mae Ai from the region around Kengtung in the Shan State of Myanmar (Burma). On the east, Chiang Mai is bordered by Chiang Rai, Lampang and Lamphun provinces. The Mae Tuen River, Ream Mountains and Luang Mountains separate Chiang Mai's south from the province of Tak. Some stretches of Chiang Mai's south also border Lamphun province. To the west, Chiang Mai is bordered by Mae Hong Son province.