the pembroke and mattawan road colonization road was constructed between 1853 and 1874 to encourage settlement in the upper ottawa valley. between mattawa and north bay, many aboriginals and early settlers made use of the mattawa river, the headwaters of which lie just north of lake nipissing. from there they would travel down the french river into georgian bay and onwards to lake superior. highway 17 between mattawa and sault ste. marie roughly traces this early voyageur route.