Blomstrandøya, also known as Blomstrandhalvøya, is an island at the western side of Spitsbergen, Svalbard. It is located in Kongsfjorden, near the northern side of the fjord, and has a roughly circular shape with a cross section of about 5 km. The island was originally believed to be a peninsula, when the glacier Blomstrandbreen extended onto the island. The highest mountain is Irgensfjellet 385 m.a.s.l. The former peninsula has an area of 16,4 km2.[1]
In 1911, the English prospector Ernest Mansfield founded Ny-London, a now derelict marble mining settlement which lies on the southwestern part of the island.[2]