Which country has the longest coastline in the world?

Canada's coastline results from its geography along three oceans, combined with an extraordinarily complex shoreline shaped by past glaciation, and tens of thousands of islands in its Arctic archipelago, each contributing its own perimeter. Measuring coastlines is tricky since a more zoomed-in map reveals more twists, but even by standard conventions Canada's total dwarfs every other country's.

Australia has a substantial coastline but a comparatively smoother shoreline with far fewer islands, while Russia, despite its size, still falls well short once Canada's fragmented northern islands are counted.

The "coastline paradox" in geography notes that measured length depends heavily on map scale, since finer measurements capture more inlets, meaning even Canada's staggering figure is something of an approximation.