swampy plain, northern Norway. Though it has no exact natural boundaries, the plain's principal section is about 60 miles (100 km) from east to west and 50 miles from north to south. The Finnmarksvidda, made up of ancient crystalline rock, is characterized by numerous small lakes and bogs, with a few branched river systems draining northward to the Arctic Ocean. Important among these are the Altaelva (west) and the Anarjåkka (Finnish Inarijoki), forming the border with Finland (east). The region is sparsely populated. Most of the inhabitants are Sami, many of whom live on their herds of reindeer.