Marten River is an unincorporated hamlet located in the municipality of Temagami, in the District of Nipissing, Ontario, Canada.
The latest census 2005 puts the town population at 87.
Marten River is considered the gateway to the Temagami area.
The main industry is mining, logging and outdoors tourism.
Ontario Northland motor coaches stop at the Trapper Trading Post on the North Bay–Hearst route.