St. Peters National Historic Site is an extensive site containing archaeological evidence of 17th- and 18th- century Mi’kmaq and Acadian communities. It is situated on the southeastern shore of Cape Breton, Nova Scotia, on the isthmus located between the shores of St. Peters Bay on the Atlantic coastline, and Bras d’Or Lake. The designated place extends along what was the Atlantic coastline in the 17th century, and crosses the isthmus within the boundaries of St. Peters Canal National Historic Site.