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 (Thailand Route 1 or Phahonyothin Road) 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.