The province is located in the valley of the Nan River. About 45 kilometers north of the city Uttaradit is the Queen Sirikit Dam, which created a 250 km² artificial lake from the Nan. The Phi Pan Nam Range reaches the northwest of the province. Most of the province was once covered with teak forests, then the major product of Uttaradit. The largest Teak tree in the world is found at the Ton Sak Yai Park in the Luang Prabang Range. The 1500 year old tree measures 9.87 m in circumference and 37 m in height - originally it was 48.5 m high, but it was damaged in a storm. Three National Parks are located in the province—Klong Tron, Lam Nam Nan and Phu Soi Dao