Thakhek (Lao language: ທ່າແຂກ), the capital of Khammouane Province, is a town in south-central Laos on the Mekong River. The Third Thai–Lao Friendship Bridge, linking Thakhek and Nakhon Phanom, Thailand, across the river, started in 2009 and was opened on 11 November 2011. Western scientists first encountered the Laotian rock rat, kha nyou (Laonastes aenigmamus), in Thakhek's market.