The Bertnem burial mounds i.e. tumulus are three large burial mounds 8 km east of Ranemslette in Overhalla municipality. They are round mounds, the largest 6-7 meters high with a diameter of almost 50 meters. Several old dwellings were found adjacent to the burial mounds.
There are remains of longhouses used for housing, approx. 40 meters long and 8 meters wide. Based on the remains of the long houses the burial mounds were dated back to the Merovingian period, ca. 550-800 AD. It is believed that the Bertnem area was the stronghold of a chieftain in Namdalen during this period.