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Lac-Sainte-Thérèse is a Dispersed Rural Community and unincorporated area in geographic Casgrain Township, Cochrane District in Northeastern Ontario, Canada. The community is counted as part of Unorganized Cochrane North Part in Canadian census data.
The community is located at the northern terminus of Ontario Highway 583 approximately 12 kilometres (7.5 mi) north of Hearst. It is on the eponymous Lac Ste-Thérèse (lake) and Ste-Thérèse Creek, which flow via the Pivabiska River, Missinaibi River and Moose River to James Bay.Doric Germain, Franco-Ontarian writer and professor, was born in Lac-Sainte-Thérèse.