The Malawi-Tanzania border is an international boundary that separates Malawi and Tanzania in East Africa. Most of the border is formed by the river Songwe, whose source is found in the mountains to the south-west of Mount Rungwe and the town of Tukuyu. The Songwe is fast-flowing and changes its course regularly in a short period of time, forming new meanders and causing the precise border location to shift and become ambiguous. A dam is currently being constructed to regulate the river's flow.