Canada is a notoriously friendly country, which is perhaps why it throws open its (metaphorical) doors to American visitors. Crossing into the country is easy enough, provided everyone in the group has appropriate ID, and navigating through the cosmopolitan cities and naturally beautiful backcountry is easy too. But all good things must come to an end. For a U.S. citizen who doesn't have special permission to remain in Canada for a longer stay, six months is the maximum stay.

How Long Can I Stay in Canada Without a Visa?

While citizens of some countries must get visas to enter Canada, a U.S. citizen doesn't need a visa to travel to Canada. Whether an American is visiting Canada for business or personal reasons, he can stay for a period of six months.

Assume you can stay for that long too, unless an immigration official tells you otherwise. Occasionally, an official will exercise her right to allow an American visitor to stay in Canada for less than six months. If that happens to you, she should inform you of that decision and the reason for it.

Note that Canadian immigration officials still have the right to refuse entry to Americans for any number of reasons. Having a DUI conviction in your past is cause for denial, but officials make that call on a case-by-case basis. Other potentially disqualifying offenses include having ties to organized crime, committing human or international rights violations, and being convicted of certain other crimes.

Does It Matter How I Cross Into Canada?

No. Whether you fly, drive or cruise into Canada, the country's residency rules are the same. Your six-month clock starts the day you arrive in Canada.

However, it's important to note that ID requirements do vary depending on the method of transportation. All visitors to Canada must prove identity and citizenship. Americans who fly to Canada must present valid passports. Even a baby must have a passport to fly to Canada.

A passport is also an acceptable ID for visitors who travel to Canada by land or sea, but these travel methods offer a little more flexibility in terms of acceptable documents. Kids under 16 are only required to show their birth certificates, either originals or copies. (If a child isn't traveling with both parents, he should also carry a notarized letter of permission from the absent parent or parents.) An adult traveler who doesn't have a valid passport can also use a passport card, an Enhanced Driver’s License, or a NEXUS, SENTRI or FAST card. If you visit Canada on a cruise that leaves from and returns to the same U.S. port, your birth certificate and a government-issued photo ID are adequate documentation.

How Can I Stay in Canada for Longer Than Six Months?

It may or may not be possible to stay in Canada longer than six months. A U.S. citizen who wants to stay in Canada for more than six months should apply for an extension. Complete the application at least 30 days before your six-month period is complete. Lots of variables affect whether the Canadian government will grant your request, including the purpose of your stay and whether you're related to any Canadian citizens.

The country's immigration department offers a simple web tool to answer questions about extending a stay. Answer a series of questions to determine if you're eligible for an extension and what steps you must take to get one.