Galsa Buyeo, also rendered as Galsa-guk or Hesi Fuyu, was an ancient kingdom founded by King of Galsa of Eastern Buyeo (Eastern Fuyu) in Manchuria, on the upstream of the Yalu River.

First king of Galsa feared that Eastern Buyeo would fall in ruins after the 22 assassination of his older brother Daeso, king of Eastern Buyeo.

Amnok(鴨淥) valley was the territory of an existing kingdom called the State of Haedu (海頭國) where its king frequently went hunting.

Galsa killed this king and set the capital in that very river.

The country was fairly independent until 68 AD,[2][3] when King Dodu (都頭) surrendered to Goguryeo and received the respectable bureaucratic position of U-dae (優台),[1] which seems to be the head of his kinship.