The area has long been inhabited by Anishinaabe peoples. French traders explored the Long Lake area in the 17th century and set up a post. The
Hudson's Bay Company (HBC) explored the area from 1776 on. Circa 1800, the
North West Company (NWC) built a trading post on Long Lake near its outlet of
Kenogami River, possibly the former site of a French post. In 1814, HBC established a rival post nearby at Gauthier Point, which was an outpost falling under
Henley House, but became a full trading post the following year. In 1819, Henley House was destroyed and Long Lake became district headquarters, until it closed in 1821 (when the HBC and NWC merged). It soon reopened as an outpost of the
Pic River post, and served as a relay post for the winter express route between Red River and
Moose Factory in the succeeding years. In the early 20th century, other trading posts opened at Long Lake, including
Révillon Frères (1906–1919), Mathe & Duphney, and Great Lake Fur Trading Company (both in operation circa 1918). In 1921, HBC moved its post from the nearby Gauthier Point to a site near the railroad station. In 1937, a pulp and paper mill opened in Longlac, and in 1942, the highway to Geraldton was built. In 1952, the place was incorporated as the Improvement District of Longlac. In 1957, the mill was taken over by
Kimberly-Clark. In 1959, the HBC operations were transferred to the Northern Stores Department. HBC divested this department in 1987 to
The North West Company, and the store subsequently closed. In 2001, Longlac was amalgamated with the former Townships of Beardmore and Nakina, and the Town of Geraldton, together with previously
unorganized areas, into the new municipality of
Greenstone. Railroad traffic from Longlac to Thunder Bay gradually declined, and this section was abandoned in 2005 and the rails were removed in 2010. The station was moved back to its original location, which is serviced by
Via Rail. ==Demographics==