Canoe Route to the West
Here, when the canoe was the principal means of travel, explorers, voyageurs, missionaries and others bound for the West, left the Ottawa River and followed the Mattawa River to Lake Nipissing, the French River and the upper Great Lakes. For over 200 years the Mattawa River formed part of the route linking the St. Lawrence River settlements with the vast interior of the continent. Among the historic figures who passed here were: Samuel De Champlain, 1615, Jean Nicolet, 1620, fathers Brébeuf, 1626, and Lalemant, 1648, Radisson and Groseilliers, 1685, La Vérendrye, 1731, Sir Alexander Mackenzie, 1794, and David Thompson, 1812.
Plaque via Alan L. Brown's site Ontario Plaques. Full page here.