The crater was formed around settlement of iceland about 1200 years ago. Bláhylur means the Blue deep pool. located close to the road F208 around 570 above sea level. The lake bears two names, the previously mentioned Bláhylur and also Hnausapollur wich is derived from the hills on the north side of the crater, Hnausar. on the south side of the crate is mountain Tjörvafell, beautifully green in contrast with the otherwise black enviroment.