Mercer (Thai:? ; English: Mae Sai is located in Chiang Rai province in northern Thailand. It is the northernmost town in Thailand, separated from tachilek in Myanmar by a river called MASAI.
The Missay River is located in Missay Town, the northernmost town in Thailand, where Missay meets Myanmar. At the same time, the Missay River is also the natural border between northern Thailand and Myanmar. There is a bridge over the Missay River, connecting Myanmar and Thailand.