The basic requirements for visiting Canada from the United States include having a valid passport, no criminal convictions and being in good health. There are additional requirements for people visiting from overseas.
Naturalized citizens who do not have passports must show valid naturalization documents to enter Canada from the United States. People traveling with children may be required to show proof of custody, and travelers under 18 years of age may need to produce letters of authorization from their parents or guardians. Those bringing pets across the Canadian border must bring proof of valid rabies vaccinations. People who have criminal records, which by definition includes drunk driving convictions, may not be allowed to enter Canada, though there are ways to receive exemptions via applications.