Tachileik (also spelt Tachilek; တာချီလိတ်, tà tɕhì leɪʔ; တႃႈၶီႈလဵၵ်း, tɑ᷆.khi᷆.lék; ท่าขี้เหล็ก, , thâː.khîː.lèk) is a border town in Shan State of eastern Myanmar. It is the administrative seat of Tachileik Township and Tachileik District and most populated city in eastern Shan State with 51,553 residents per 2014 census count, ahead of Kyaing Tong, but only 4th statewide. It faces Mae Sai in Thailand, and is home to one of Myanmar's seven official border trade posts with Thailand. Tachileik was a border crossing used in the opium trade from the Golden Triangle and was the town that the drug lord Khun Sa used to live in. On 24 March 2011 a magnitude 6.8 earthquake struck the region very close to Tachileik. It caused some damage as far away as Chiang Mai. On 24 March 2012 a bomb wounded 2 people at the Regina Hotel golf course in Tachileik, followed by a second bomb that exploded an hour later. The border trade post with Thailand opened on 16 March 1996. In 2022, total trade volume at the border post stood at . In 2009, it was reported that Tachileik vendors openly sold endangered animal parts. Located immediately following the bridge that divides Myanmar and Thailand is a marketplace that sells a large variety of products, including DVDs, perfume, clothing, luggage, and wine. Tachileik once had the reputation as a distribution nexus for heroin and ya ba (methamphetamine pills) moving from rural Myanmar to the world market. The Western media's reports said the drugs were manufactured and distributed by a number of armed groups in Myanmar. The crowning tourist attraction is a large gold-colored stupa, which, among other things, showcases the seven days of the week. The idea is for a pilgrim to go to the spot which has the day he/she was born known as the planetary post, and do a simple spiritual worship. West of town there are hiking trails, though currently they are designated for locals, not for tourists. There is an Akha hill tribe, over an hour's walk north-west of Tachilek called Ho Yu.