In the 1940s after the Chinese Civil war, remnants of the losing nationalist army fled to this then remote area of Thailand and set up their own little enclave, supported by opium production. In the 1980s the Thai government integrated this enclave into Thai society and as part of the process introduced a policy of substituting opium production for growing tea.
Drive on highway 1089 between Chiang Mai and Chiang Rai. The turn off is next to a police station. From here travel about 13km on some of the most amazingly curvy roads imaginable.
By Public Transport, take a Mai Sai heading bus from Chiang Rai Bus Station and get down at Pasang (approximately an hour, 25B), somewhere there's a junction which shows different directions for Mae Sai and Mae Salong, or simply ask the friendly bus conductor to inform where to get down.
There would be blue songtaews waiting at the T-juction for passengers going up mae salong. The songtaew charges 80B one way. After a 45 minutes ride, the songtaew will stop infront of a 7-11 shop at the mae salong town.
It is very convenient to rent a motorbike to wandering around the hills and valley. Renting fee is 200 baht per day. however, it comes with empty tanks so need to re-fuel before any ride.
Excellent Tea. Local and Chinese.
Tea sets from China (the same set costs 8x as much in Hong Kong).
Chinese candies and fruits.
yunnan noodles with lot of mushroom (restaurant or morning market), or with bean gravy; Papa cake (outside morning market), soybean drinks with deep fried dough stick 油条(morning market)
For backpackers, there are a few guesthouses available on the town.