In Chiang Mai you can find an office of the Tourist Authority of Thailand on Chiang Mai-Lamphun Road. It's in a small building on the eastern bank of the Mae Ping River, opposite the New Bridge, and opens daily 8:30 to 4:30.
Lampang's tourist office is on Thakhraonoi Road near the clock tower. The TAT office in Lamphun, opposite the main entrance to Wat Hariphunchai, has irregular hours, but is generally open weekdays 9 to 5.
Tourist information about Nan Province, Nan itself, and Phrae is handled by the Tourism Authority of Thailand's regional office in Chiang Rai.
Tourist Authority of Thailand (Chiang Mai) (105/1 Chiang Mai-Lamphun Rd., Chiang Mai. 053/248604. www.tourismthailand.org).
Tourist Authority of Thailand (Chiang Rai) (448/16 Singhaklai Rd., Chiang Rai. 053/744674 or 053/744675. www.tourismthailand.org).