| Sunday Lake | |
| Location: | Arthabaska Regional County Municipality, Centre-du-Québec, Quebec, Canada, |
| Coordinates: | 45.88°N -71.5103°W |
| Outflow: | Rivière au Pin |
| Catchment: | NaNkm (-2,147,483,648miles) |
| Area: | 0.85km (00.53miles) |
| Frozen: | End of December to beginning of March |
| Pushpin Map: | Quebec |
Sunday Lake (in French: lac Sunday) is a lake located in the municipality of Saints-Martyrs-Canadiens, in the Arthabaska Regional County Municipality, in the administrative region du Centre-du-Québec, in Québec, in Canada.[1] It is headlake of the rivière au Pin, about upstream from Breeches Lake.
The lake, long and wide, is private and the Brothers of the Sacred Heart own it; the banks are almost entirely wooded. Camp Beauséjour is a welcoming place for groups and families. Recreational trips, a family camp, and fishing are available.[2]