The Northern Hemisphere has land almost all the way to the pole; the Southern Hemisphere runs out of country at around 55° south, with nothing but ocean and then Antarctica beyond. That asymmetry shapes both answers.
Furthest north
Canada reaches furthest north of any country: Cape Columbia on Ellesmere Island sits at about 83°06′ N, less than 800 km from the North Pole. Greenland's northern tip is slightly further still, but Greenland is part of the Kingdom of Denmark rather than an independent country — which, if you count it, makes Denmark the northernmost sovereign state. Among fully independent mainland-Europe countries, Norway reaches about 71° N at the Nordkinn peninsula, and Svalbard (Norwegian) extends past 80° N. Russia's Arctic islands also pass 81° N.
The northernmost capital
Reykjavík, Iceland, at about 64°08′ N, is the world's northernmost capital of a sovereign state. Helsinki, Oslo, Stockholm and Tallinn follow. Nuuk, in Greenland, is further north but is a territorial rather than a national capital.
Furthest south
Excluding Antarctic territorial claims, Chile reaches furthest south. Its mainland ends at Cape Froward at about 53°54′ S, and Chilean islands in the Cape Horn group extend to roughly 56° S — the settlement of Puerto Toro is often called the southernmost town on Earth. Argentina is close behind at Tierra del Fuego. New Zealand's main islands stop around 47° S, though its uninhabited subantarctic islands reach past 52° S.
The southernmost capital
Wellington, New Zealand, at about 41°17′ S. No other national capital comes close — Canberra, Montevideo, Buenos Aires and Santiago are the nearest, all north of 42° S.
Why there is no southern Canada
Look at a globe from below and the reason is obvious: south of about 55° S there is simply no land except the Antarctic Peninsula. The Southern Ocean circles the planet unbroken. So while people live year-round above the Arctic Circle in Norway, Russia, Canada and Greenland, the only permanent residents south of the Antarctic Circle are researchers on scientific bases.
For the bigger picture of what lies south of the equator, our Southern Hemisphere guide maps it out.
Southern Hemisphere countries →