Sukhothai is located in the valley of the Yom River on the lower edge of the northern region, 427 kilometres north of Bangkok, and covers some 6,596 square kilometres.
The Khao Luang Mountain Range, with its four main peaks: Khao Phu Kha, Khao Phra Mae Ya, Khao Chedi, and Pha Narai, lies within the Ramkhamhaeng National Park in the south of the province. The Si Satchanalai National Park is located in the north-west, protecting the mountainous forest areas of the Phi Pan Nam Range at the northern end of the province.