Lumpari) is a large bay devoid of islands in the main island of Åland, Finland, bordered by Sund to the north, Lumparland to the east, Lemland to the south and Jomala to the west.

Extraterrestrial origin was first proposed in 1979, but not until 1993 was the impact structure finally confirmed.

Long shatter cones have been discovered in the southwestern part of the bay.

Between Pleistocene sediments and crushed rapakivi granite bedrock there is a layer of Paleozoic (Ordovician) limestones.

This makes Lumparn one of the few places in Finland where fossils have been found.