The name Mistassini came from the
Cree or
Montagnais , and means "large rock"; it probably refers to a large
glacial erratic stone, about high, located near the outlet of Lake Mistassini into the
Rupert River. Over the centuries, it went through many name changes and different spellings. In 1664, on a map by Ducreux, this lake was known as
Outakgami. On maps by Jolliet (1684), Jaillot (1685) and Franquelin (1688), the lake was identified as
Timagaming. In 1703, the cartographer
Guillaume Delisle used the same name, along with the name
Mistasin. Laure (1731) and
Bellin (1744) showed on their maps the name
Lake Mistassins. Other spelling variations of this First Nations designation included:
Mistacinnee, Mistacsinney, Mistasinne, Mistasinia, etc. In 1808, James McKenzie of the
North West Company used the name
Lake Mistassini in his writings, the first use of the name in its current form. Nevertheless, other variants persisted long after: for instance, the explorer James Clouston inscribed
Mistassinnie in his diary of 1820, while the geologist Robert Bell mentioned in 1880 the name
Misstissinny. Yet, thereafter,
Mistassini became the accepted form, as evidenced by the map of the province of Quebec drawn in 1880 by Taché, and the expedition report published by
Albert Peter Low in 1885, and in his Annual Report of 1900, Bell also adopted the current spelling. ==Pre-contact==