Trapping pits, into which hunted animals would have fallen, are the most visible remains telling of the large-scale hunting of reindeer. These pits are typically found in groups that can include hundreds of individual pits. For example, over 1600 trapping pits were recently found along River Lätäseno in eastern Enontekiö using detailed airborne laser scanning data from a 25x3-km area. Nowadays, trapping pits show up as shallow depressions that range in diameter from 1.5 m to 3 m and in depth from 0.5 m to over 1 m. Originally, they have been much larger and deeper, and wooden structures or spikes may have been placed within the pits, as some archaeological excavations have shown. Fence structures may also have been in place, directing the animals to the pits or in-between the pits.
The location and direction of the trapping pit systems hints at the seasonal migrations of wild reindeer herds. The most extensive system of trapping pits in Kilpisjärvi has been found in the Siilasvuoma River Valley, and the pits continue on the Norwegian side of the border.
Wild reindeer hunting appears to have been the most important form of subsistence for millennia over wide areas in Lapland. None of the trapping pits in Kilpisjärvi region have been dated so far, and therefore we do not know how old they are. They can date back through the Stone Age and Early Metal Period (between ca. 8 000 BC–300 AD) to the Iron Age (ca. 300–1300 AD). Most radiocarbon-dated trapping pits in Finland are between 5000 and 2000 years old.