As of 2015, the requirements for crossing the border between the United States and Canada include presenting a valid passport or proper travel documents, such as a NEXUS card or a FAST card, explains The Peace Bridge. The exact border-crossing requirements vary by age and depend on the traveler's citizenship, his entry purpose, the length of the traveler's stay, whether the traveler imports or exports items or live animals, and whether the traveler is entering the United States or Canada.
Visitors can enter Canada by car with a NEXUS card or by presenting a naturalization certificate or birth certificate with a government-issued photo identification card, highlights USA Today. However, re-entry into the United States requires a passport.
People entering the United States by land can use WHTI-compliant documents such as enhanced driver's licenses, military identification cards, and U.S. merchant mariner documents, reports the U.S. Customs & Border Protection. U.S. armed forces members that are on official orders can use military identification cards, while U.S. citizens on authorized maritime business can utilize the U.S. merchant mariner documents.
Travelers planning to work or study in Canada need the appropriate visa travel document, notes the U.S. Department of State's Bureau of Consular Affairs. However, tourists can visit Canada without a visa for up to 180 days.