Which city is the southernmost capital of a sovereign state?

Wellington is the southernmost capital of a sovereign state.

New Zealand’s capital lies at about 41°17′ south latitude, on the southwestern tip of the North Island beside Cook Strait. That position makes Wellington the world’s southernmost national capital among sovereign states. The city’s harbor, steep hills and exposed location give it a distinctive setting between the North and South Islands.

Wellington has served as New Zealand’s capital since 1865, when the government moved there from Auckland. Its central location made administration and communication with both islands more practical, while its harbor provided an important transport link.

The answer is sometimes confused with Canberra, Buenos Aires or Santiago, but all three lie farther north. Wellington is also distinct from New Zealand’s largest cities by population; Auckland is larger, but it is not the capital. The city is known by Māori names including Te Whanganui-a-Tara and Pōneke, and its compact urban area is hemmed in by the harbor and surrounding ranges.