Canada has the world's longest coastline, measuring more than 200,000 kilometres when its many islands are included.
Canada borders three oceans: the Atlantic, Pacific, and Arctic. Its coastline is extraordinarily long because the country contains the Arctic Archipelago, Hudson Bay, numerous Pacific and Atlantic islands, and many deeply indented bays and inlets.
Exact measurements vary according to the scale and method used, a problem known as the coastline paradox. Common references give Canada a coastline of about 202,080 kilometres, while some sources use different figures because coastlines become longer when measured in finer detail.
Russia, Indonesia, and Greenland also have very long coastlines, but none exceeds Canada's commonly cited total. The result depends on counting marine islands and on the measurement convention, yet Canada remains the standard answer in world geography.