The Sammallahdenmäki is a hill in the western Finnish town of Lappi, which belongs to the city of Rauma. There are about 36 Bronze Age cairn graves on the hill.
The burial ground is an important archaeological site in the Nordic countries and was added to the UNESCO World Heritage List on December 1, 1999. The cairns, which can also be found on Bronze Age sites in Denmark and Sweden, were made around 1500 to 100 BCE. The site was built on the east coast of the Gulf of Bothnia, and since then the land has risen by around 30 m since then due to the post-glacial uplift, so the tombs are now more than 15 km from the sea.
The cairns are mentioned in local literature as early as 1878. The first investigations were carried out in 1891, during which four graves and the so-called “church floor”, which is unique in the Nordic countries, were examined. The "church floor" is an irregular, square stone field that was probably used as a grave, although the graves were usually round. During the investigation, burned human bones were found, which is why it is assumed that the burial rituals of the time were cremations. Bronze fragments from grave goods were also found in a stone box in one of the graves.
When analyzing the age of the graves using the radiocarbon method, it was found that the oldest graves date from 1300–1000 BCE, and the youngest date from between 170 and 82 BCE. During further excavations in 2003 and 2004 near the graves, Bronze Age dwellings were found that are roughly the same age as the younger graves. They were identified by the remains of fireplaces and pieces of bronze.