We have no Stonehenge in southern Vestfold and no giant collections of standing stones. But some of the stone circles rank among the grandest and most interesting in Norway. So far, archaeologists that have delved into their secrets seem to think that most of them are tombs from the early Iron Age (from 500 BC. 550 AD.). It is also possible that they could have been places of Pagan ceremony.
Stone circles can be defined as large upright stones placed in specific formations, usually round. In this district there are also know to be ship-shaped, square and triangular ones. Counting those that are known to have collapsed or been removed over the years, there were at least 65 - 70 such ancient monuments in Southern Vestfold.
Among the best of these, is Istrehågan the municipal boundary between Larvik and Sandefjord. It consists of one large and one small ship-shaped stone setting, three circular and single menhirs. Especially nice is the large ship setting, which with its 18 stones mark clearly the boats gunwale rising from amidships to the 3.5 meter tall stems. The "Ship" is 24 meters long and nine meters at its widest. Archaeologists have found the burned remains , dated to 400 years after Christ.
Many of the country's ancient monuments, today lie as ruins after being raided, others are so overgrown that they are barely visible. It is therefore important that some of the ancient monuments are cleared and restored manually. Istrehågan burial was examined by Museum of National Antiquities and Tjølling historical society in the years 1959-1962 and circles were restored, all the stones had been toppled in earlier times.