Pathein (Burmese: ပုသိမ်မြို့; MLCTS: pu. sim mrui., Burmese pronunciation: [pəθèiɴ mjo̰]; Mon: ဖာသီ, [pha sɛm]), also called Bassein, is a port city with a 2004 population estimated at 315,600, and the capital of the Ayeyarwady Region, Burma. It lies on the Pathein River (Bassein), which is a western branch of the Irrawaddy River.