What countries does Canada have borders with?

Countries around the world differ in size, population, and how many neighbors they have. Some countries have many neighbors (for example, Russia and China) while other have very few. States such as Iceland, Australia, and Sri Lanka occupy islands and share a border with one country or have no neighbors. Canada is an example of a non-island country that shares borders with one country only. Other such states are San Marino, Portugal, Denmark, South Korea, Gambia, and the Vatican City, among others.

United States of America is the only country that forms the border of Canada by land. The Canada-US border is a terrestrial border and the longest border in the world. It is known as the International Boundary and includes maritime boundaries on the Arctic, Pacific, and Atlantic coasts and the Great Lakes. The border is 5,525 miles or 8,891 kilometers long, including 1,538 miles or 2,475 kilometers shared with Alaska.

Canada is the largest nation to have a terrestrial border with one country only. The Canada-US border is known as the longest undefended border in the world. It is guarded by civilian law enforcement officials only, in contrast with the security measures on the US-Mexico border, which is one-third the length of the International Boundary. The United States-Mexico border is patrolled and guarded by US customs and immigration personnel as to prevent drug trafficking and illegal migration.

Parts of the Canada-US border cross through heavily forested regions and mountainous terrain. Significant portions of the border cross the Saint Lawrence River, the Great Lakes, and remote prairie farmland.

Canadian citizens and residents who plan to travel to the country’s only neighbor should present a valid passport. When entering the US by water or land, Canadians can present any of the following: an enhanced identification card, an enhanced driver's licence, a Free and Secure Trade (FAST) card, a NEXUS car, or a passport. Canadians flying to the US are required to present a passport as to confirm their identity and citizenship. A NEXUS card can be used at self-serve kiosks found in designated Canadian airports.

While Canada has borders with one country only, there are agreements between the governments of the U.S. and Canada to make the shared border a secure place. One agreement is the Safe Third Country Agreement, which aims to manage the flow of refugees. Under this agreement, persons who seek refugee protection are required to make a claim in the country of arrival (Canada or the United States). This agreement does not apply to stateless persons who are habitual citizens of the US and to US citizens.

Regarding other border crossings, there are 4 airports straddling the borderline between Canada and the U.S. - Coronach/Scobey Border Station Airport, Piney Pinecreek Border Airport, Avey Field State Airport, and Coutts/Ross International Airport. Before the entry of the U.S. into the Second World War, these airports were used to transfer US aircraft for delivery to Great Britain.

Finally, there are US land exclaves contiguous with Canada, including Northwest Angel, Point Roberts, Alaska, Elm Point, and others.