The Altafjord is a fjord in Alta Municipality in Finnmark county, Norway. The 38-kilometre (24 mi) long fjord stretches from the town of Alta in the south to the islands of Stjernøya and Seiland. The 200-kilometre (120 mi) long river Altaelva empties into the fjord at the town of Alta. At Stjernøya and Seiland islands, the fjord splits into two straits before emptying into the Norwegian Sea. Some of the larger side-branches off the main fjord include Langfjorden, Kåfjorden, and Korsfjorden.