Istrehågan

thumb|right|250px|Rock setting resembling a ship. Istrehågan is an ancient monument at Jåberg on the Sandefjord-Larvik border in Vestfold, Norway. It is home to some of the largest stone settings in the Nordic countries. Nearby Haugen farm in Sandefjord is home to Vestfold County's largest petroglyph site. The rock carvings at Haugen farm are Vestfold County's oldest ancient monument. It is an ancient burial ground which dates to the time of the Roman Iron Age around 500 - 600 AD. It is located two kilometers northwest of Hemskilen Nature Preserve in a forest known as Marumskogen.

Large stone settings resemble a ship. The largest "ship" is long, and meters broad. Most rocks are about tall, while some are as high as . Archaeological excavations made in 1959-1961 uncovered remains of bones, bear claws, pottery shards, a brooch, and more. Most stone settings are dated to the Migration Period around 400-500 A.D. There are marked hiking trails leading to Istrehågan through the Marum forest, for example from Store Bergan skole. There are also agricultural symbols here which were etched into the hillside during the Bronze Age, 1500-500 B.C.E.