Uttaradit is one of the northern provinces of Thailand. Neighboring provinces are (from south clockwise) Phitsanulok, Sukhothai, Phrae and Nan. To the east it borders Xaignabouli of Laos.
The province is located in the valley of the Nan River. About 45 kilometers north of the city Uttaradit is the Queen Sirikit Dam, created a 250 km˛ artificial lake from the Nan.
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. 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.