Even if you don't (yet) distribute your products in Canada, there are two recent developments in Canadian trademark law that may be worth noting.
First, in 2019, Canada will be moving from the a first-to-use trademark system (as we have in the US) to a first-to-file system for priority of rights. This means that a party with knowledge of, but no rights in, your US trademark may nonetheless apply to register your mark in Canada before you can get around to it. Having beat you to the Canadian Trademark Office, their application will block your later application, as unfair as that may seem. Accordingly, we are likely to begin seeing "trademark squatting" there, as we do now in China, where nefarious folks file to register a mark they see in the US before the legitimate owner has expanded to Canada.
Second, your trademark rights in Canada are predicated on your use of the mark in Canada. In earlier cases, the Canadian Trademark Opposition Board had taken the position that "use" required that you operate a physical location in Canada or ship directly into Canada. Simply having a branded website that was accessible from Canada was not deemed to be sufficient. But a recent decision of the Federal Court of Canada has overturned the Trademark Opposition Board ruling and held that Canadian law now recognizes "use" as possibly comprising providing "retail store services," even if you do not have a "brick-and-mortar" establishment there and even if you do not ship product directly to customers in Canada. This can be an alternate way of securing rights to your mark in Canada.