Our school uses Canada: A Nation Unfolding. It is an older secular textbook (copyright 2000) published by McGraw-Hill Ryerson. I would definitely recommend it. It’s old enough that it has a fairly “conservative” viewpoint, compared to what newer textbooks tend to have. The only downside is that it doesn’t have any teacher or student materials.
It isn’t in print anymore, so check out eBay like Peter suggested. I have also purchased some on Amazon.