Can I travel to Canada directly from the US with a green card and an?
Your plan wont work if you are coming to Canada by air and you need an eTA because you need a valid passport to apply for the eTA. The eTA requirement is for everyone from a visa-exempt country who flies to or in Canada, regardless of how long you plan on being in Canada. I dont know if your plan would work if you crossed at a land border; Ive only encountered travelling on an expired US passport which I know is not your case. My suggestion is to contact CBSA (Canadian Border Services Agency) and get the information straight from the horses mouth, so to speak. As well, you should contact US Customs and Border Protection to make sure you can get back into the US.