what are the requirements for legal permanent residents travelling to canada?

A passport is the ideal identification for United States residents.

Citizens born in the U.S can show a birth certificate, certificate of citizenship or naturalisation, plus photo identification.

Permanent residents of the U.S. who are not citizens need to bring their U.S. Permanent Resident Card (‘green card’).

If you are a green card holder in the U.S., you may enter Canada using your green card. You do not need a visa. See 1st site below and read section on "permanent residents." On 2nd site scroll way down and read 2nd paragraph under "Visitor Visa Exemptions.

permanent residents of which country?