How Many Miles Is It From Seattle Wa. To Canada ?

I imagine you mean the border of Canada, not any particular town or city. To Vancouver it is about 130 miles.
To the border town within the U.S.A, Bellingham, it is less than 100, and the first town in Canada before you get to Vancouver is Delta, which is about 115 miles
So it is not such a long drive, and could be accomplished easily in a morning.
There are good maps available free on line, just type in Seattle to Vancouver to your search engine.
Some of them will even tell you where you can fill up and stop over for a bite to eat. Some of them will calculate from major town to major town. Happy travelling across the border.

The distance between Seattle, WA and Victoria, British Columbia is 74.0 miles(119.0 km). Victoria is on the Border of Canada and the US