Mae Sai, is the district town of Mae Sai District in the far north of Chiang Rai Province, Thailand. Mae Sai is a major border crossing between Thailand and Myanmar; the town of Tachileik, in Shan State is across the bridge. Asian Highway Network AH2 crosses the Mae Sai River to the town of Tachileik in Myanmar. The town of Mae Sai and Tachileik are the bi-national conurbation shared between Thailand and Myanmar.