That one is clearer, at least. TL;DR for the easiest experience - bring both passports, enter and leave each country on the respective passport, and if anyone i

That one is clearer, at least. TL;DR for the easiest experience - bring both passports, enter and leave each country on the respective passport, and if anyone is confused, show both passports and explain that you're a dual citizen. To enter and leave the US, you're supposed to use a US passport and not a Canadian one. To enter Canada, it's smoothest and fastest to use your Canadian passport, but they do have an exception for US-Canadian dual citizens that allow you to use a US passport. If you use a US passport and claim to be a Canadian citizen at a CBSA checkpoint, they might send you to immigration screening to verify your claim, especially if you don't also show some evidence of citizenship like your citizenship certificate. If you use a US passport and claim to be a Canadian citizen to a commercial transportation company like an airline on the way into Canada, they're advised to do "due diligence", but there is no specific set of documentation required. The citizenship certificate would probably satisfy them, and in practice many times maybe the US passport by itself too.