Ellenvatn or Ellenvatnet (Kven: Ellijärvi) is a lake located Sør-Varanger Municipality in Finnmark county, Norway. The lake has an area of 10.93-square-kilometre (4.22 sq mi).The lake is located within Øvre Pasvik National Park, just northwest of the lake Ødevatnet. Ellenvatn is the park's largest lake, located centrally in the park and is drained from the north through the river Ellenelva. Ellenvatnet is shallow and has a long and crooked shoreline with a large number of small islands.