Alnaelva, also known as Alna or the Alna River, is a river the runs through Oslo, Norway, from Alnsjøen to the Oslo Fjord at Bjørvika. It also drains Breisjøen, Steinbruvann, Tokerudbekken and Østensjøvannet. Large sections of the river run in culverts and the river is highly polluted, partially because it is used as a sewer drain.