marasmus

If my sibling immigrates to Canada and I want to take her my used car from the US, can I simply cross the border and deliver the car to her or will there be hurdles with her registering the car in Canada?

iaink

Potentially lots of hurdles. Some US spec vehicles cannot be imported to canada without substantial modification. Try googling something like "importing a vehicle to canada", that should send you somewhere near the transport canada website which has all the details.