Siljan (lake) in the center of the ring, distant from the ring sediments and from Gravberg-1. This well went to a depth of . The hole produced gases and oily magnetite sludge similar to those found in Gravberg-1. Siljan (lake) Siljan, in Dalarna in central Sweden, is Sweden's sixth largest lake. The cumulative area of Siljan and the adjacent, smaller lakes Orsasjön and Insjön is . Siljan reaches a maximum depth of , and its surface is situated above sea level. The largest town on its shore is Mora. The lake is located around the southwestern perimeter of the Siljan Ring (Swedish:
Siljan Ring Ordovician and Silurian sedimentary rocks deformed by the impact are rich in fossils. The area around the Siljan Ring has been the site of recent prospecting for oil and natural gas, though none of the projects has so far been commercially viable. There are large deposits of lead and zinc near Boda at the eastern edge of the Ring. There are several lakes in the vicinity, the largest of which is Siljan on the south-southwestern edge of the crater, with the smaller Lake Orsa to the west and Skattungen and Ore on the northeastern margin. The Siljan Ring consists of