Pathein (Burmese: ; MLCTS: pu. sim mrui., Burmese pronunciation: [pəθèiɴ mjo̰]; Mon: , [pha sɛm]), also called Bassein, is a port city with a 2004 population estimated at 215,600, and the capital of the Ayeyarwady Region, Burma. It lies on the Pathein River (Bassein), which is a western branch of the Irrawaddy River.