• A valid U.S. passport is required for all international flights to Canada.o' canada image by Kathryn Palmer from Fotolia.com
  
  Canada is the second-largest country in the world and receives more than 5 million visitors each year. If you are planning a trip to Canada, it is important to know the entry requirements to ensure a hassle-free arrival into the country. All United States citizens who travel to Canada by air are required to hold a valid passport. Various other documentation can be used for entry when American citizens enter the Canadian borders by land.
  
  

From the U.S. by Air

• Travelers need to supply proof of U.S. citizenship and proof of identity when entering Canada from the United States by air. The U.S. passport satisfies all proof of citizenship and identity requirements for entry into Canada. U.S. citizens who arrive in Canada from a third country--not the United States--are also required by law to provide a valid U.S. passport upon arrival. Americans who wish to visit Canada on a short trip--up to 180 days--do not need to apply for a visa.
  
  

From the U.S. by Land

• U.S. citizens who wish to enter Canada by land need to supply a valid U.S. passport when they arrive at the border crossing. For citizens who do not have a passport, an U.S. passport card is another form of documentation allowed for entry, which is designed specifically for land-travel. A passport card is cheaper than a regular passport book--as of November 2010, the price for an adult passport card is $55. The passport card allows land travel between the United States, Canada, Mexico, Bermuda and the Caribbean. The passport card is wallet-sized and valid for ten years upon issue.
  
  

NEXUS Card

• NEXUS cards expedite border crossings into Canada, and U.S. citizens can choose to hold a NEXUS card instead of a passport when traveling to Canada. NEXUS cards are for low-risk, pre-approved travelers. An application and registration process is mandatory to become a NEXUS cardholder, and applicants must have fingerprints taken and give an interview to a Canada Services Border Agency (CBSA) or an U.S. Customs and Border Protection (CBP) officer. Applications and interview locations are available on the CBSA website.
  
  

Children Under 16

• Children who are under 16 years of age are only required to show proof of U.S. citizenship when traveling to Canada by land, such as a birth certificate, naturalization certificate or Consular Report of Birth Abroad. The same rules apply to those under 19 years of age, when traveling with a school or religious group.