Gardnos crater (Gardnoskrateret) is a meteorite impact crater in the area known as Nesbyen in Nes municipality in the county of Buskerud in Norway.
Gardnos crater is 5 km in diameter, and was created when a meteorite with an estimated diameter of 200-300 m struck 500 million years ago. At first this site was believed to be a volcanic crater, but in 1990 two scientists discovered that it was in fact formed by meteorite impact.
The original bedrock in the area was fractured and a powder of crushed rocks was forced into all the fractures. This is the origin of the peculiar rock in this area. It is possible to drive into the centre of the crater, which makes the Gardnos crater one of the world's most accessible meteorite craters. There are two trails through the surrounding natural region, with information signs describing the unique geology of the area.