Phayao is the capital of the province of the same name. The province is hemmed in between Nan, Phrae, Lampang, and Chiang Rai provinces. In the northeast it borders Laos. Phayao’s foundation took place in 1096. It was an important principality in the Lanna Kingdom. King Ngam Muang appears next to Kings Mangrai of Chiang Mai and Ramkhamhaeng of Sukhothai in the Three Kings statue in Chiang Mai.
Phayao must have been an important city. During the Burmese rule of Lanna from 1558 until 1774 the city was deserted though. The city is famous for its lake, locally called Khwan Phayao. If you can hire a bicycle it is worth cycling around the lake. It takes about one to one and a half hour. Cycle counter clockwise is my advice.
Wat Tilok Aram is a small temple on the lake. You can get there by boat. There is only a Buddha statue. The temple itself is submerged.
As in all Thai cities there are a number of interesting Buddhist temples. Wat Analayo Thipphayaram is the most interesting, as far as we are concerned.
If you have time Wat Si Khom Kham, Wat Anal Yothippyaram and Wat Phra That Chomthong are also worth visiting.
The nearby Phu Sang National Park is also worth visit. Tourism has bypassed Phayao in the past but this seems to be changing.