Could someone give me a definitive answer as to what is required to bring a dog from Canada into the US?

I'm a US citizen, the dog is in Canada and we would be adopting it. It looks like if we cross the border with our own dog, it's just a current rabies certificate. We would be adopting from a friend's mom, not an official organization. If it weren't for the original owner's name on the rabies certificate, I'd just bring it across as if we had always owned it.

Has anyone done this that can provide insight? I've been reading online and I'm not finding a clear answer.

ETA: if it matters, the dog is ~5yo.

It was 20ish years ago, that we bought a puppy from folks in NB. We came back across the border (in Houlton) with our our 9ish y/o daughter holding said puppy. When asked if we had bought anything, she held up the puppy and said "just her". We were waved on. Sorry, have no idea what the current situation is.

It's not that complicated. Start here:

https://www.aphis.usda.gov/aphis/pet-travel/bring-pet-into-the-united-states/pet-travel-dogs-into-us

Assuming you take possession in Canada then it's just a plain old pet. You are not "importing for resale or (fee based) adoption". See:

https://www.aphis.usda.gov/aphis/resources/permits

Even better, if you read through all the links (CDC, etc.), CA is not on any list of countries with canine diseases. Technically you don't even need a rabies certificate.

That said, IIWY I would go to it's Canadian vet and pay for a certificate of ALL of it's vaccinations in your name, and while there pay to get it ISO chipped off it isn't already, then have the chip registered in your name and carry that documentation as well.

As far as your state is concerned, you can either play their game (follow the link at the USDA site) or just ignore it.