Fort Frontenac was a French trading post and military fort built in 1673 at the mouth of the Cataraqui River where the St. Lawrence River leaves Lake Ontario (at what is now the western end of the La Salle Causeway), in a location traditionally known as Cataraqui. It is the present-day location of Kingston, Ontario, Canada. The original fort, a crude, wooden palisade structure, was called Fort Cataraqui but was later named for Louis de Buade de Frontenac, Governor of New France (Count Frontenac), who was responsible for building the fort.