As of July 2008 - Not for a US citizen, just a birth certificate and a government issued photo ID, such as a driver's license.
Other nationalities are required to have a passport.
no. you'll need...
No you do not. Passports are for entering other countries. The only way you would need a passport to enter an Indian reservation would be if the reservation was in another country.
What do you mean if "you are in Mexico"? Do you mean if you are a Mexican citizen? If you are a Mexican citizen, then Yes, you need a valid Mexican passport to enter Canada. A Canada visa is not...