The river Vefsna (Southern Sami: Vaapstenjeanoe or Swedish: Vapstälven) is the largest river in Nordland county, Norway. It is 163 kilometres (101 mi) long and drains a watershed of 4,122 square kilometres (1,592 sq mi). Its headwaters lie in the mountains of Børgefjell National Park at the lake Simskardvatnet. The river runs through the municipalities of Hattfjelldal, Grane, and Vefsn. The southern parts of the river are sometimes called the river Susna. The river flows north, not far from the Swedish border, and some of the minor tributaries come from Sweden. At Mosjøen, the river discharges into the Vefsnfjord.