Seiland National Park (Norwegian: Seiland nasjonalpark) lies in Alta Municipality and Hammerfest Municipality in Finnmark county, Norway. The park includes the majority of the island of Seiland, the second-largest island in Finnmark after Sørøya. The park includes two glaciers: Seilandsjøkelen and Nordmannsjøkelen (the northernmost glaciers in Scandinavia). The highest point in the park is the 1,078-metre (3,537 ft) tall mountain Seilandstuva. The 316-square-kilometre (122 sq mi) park was established on 8 December 2006. The 9.6 square kilometres (3.7 sq mi) of the water inside the park's area, includes the surrounding sea and many fjords including the Nordefjorden, Sørefjorden, and Flaskefjorden.^[1]

The name of the island must be very old, from Proto-Norse *Sai-aujo ("sea-island"), and the Northern Sami language name Sievju is probably an old loan and reflection of this form. In Norse times, the name was transformed first to *Sæ-ey, and then to just *Sei. The last element land means "land" or "island" is a later addition.