Radiocarbon dating of items at an archaeological site discovered by workers at Costa Rica’s Reventazón Hydroelectric Project has revealed the 66 human settlements at the site to be 12,200 years old, which would represent the oldest find of its type in Central America to date, the Costa Rican Electricity Institute announced in a press statement on Wednesday.

Exploration of the site, which covers a total of 1,018 hectares in the canton of Siquirres, began under the supervision of the National Archaeological Commission (CAN) in 2006, but the delicate task of extracting and recovering the site’s artifacts began only this year.

Now, radiocarbon dating has revealed that the items recovered at the site date to the Paleo-Indian Period, which spans from approximately 15,000 B.C. to the end of the Pleistocene Ice Age, or about 7,000 B.C. The period marks the first know inhabitation by Homo sapiens of what later became known as the New World, during a period when massive creatures like the American mastodon still walked the Earth.

Amongst the 66 human settlements discovered along both banks of the Reventazón River, archaeologists have managed to identify and recover petroglyphs, foundations for dwellings, stone tools, pottery, cooking utensils, items used for human burial, and other items – even stone roads or walkways.

Tools used for carving, hunting and gathering were also discovered, and items indicating that humans at the ancient settlements may have even engaged in small-scale farming were also found.

Dated at 12,200 years old, the items are the oldest evidence of human settlement ever discovered in the region.

Most of the items will be transferred to the Department for Protection of Cultural Heritage at Costa Rica’s National Museum, though some items that due to their size or weight cannot be transported will stay in place to be located in a cultural center that will be built on the premises of the future hydroelectric plant.