Dalhousie Lake, Ontario.
Postcard of Dalhousie Lake, which is just north-west of McDonalds Corners, Ontario. The cottages shown are on the west side of the lake. Very little has changed, except I think they are now permanent homes.
This enlarged section shows the back of a vintage automobile at the far right edge, which is about the only thing which helps to date the photo. Note also that the man seems to be wearing a more modern bathing suit rather than a full-body costume common before WW2.