That's Lake William, in the Turtle Mountain area in southwest Manitoba. There is also Lake Adam and Lake Max around there, all of which have campsites... nice places to camp... but a 3 hour drive from Winnipeg. We also like Big Whiteshell campground -
http://www.whiteshell.mb.ca/ but we weren't going at the time with children so I'm not sure what it has in that area. There's probably camping all around Lake Winnipeg and Lake Manitoba which is really nice, and different from the smaller lakes. I'm so excited about summer! Too bad I have to take a course for 2 weeks of it... but that's okay!