What was the largest empire by land area in history?

The British Empire was the largest empire by land area in history. At its territorial peak around 1920, it covered about 35.5 million square kilometres—more than a quarter of the world’s land area.

Its territories included the United Kingdom’s colonies, dominions, protectorates, mandates, and other administered lands across every inhabited continent. They ranged from Canada, Australia, and India to large parts of Africa, the Caribbean, the Middle East, and the Pacific. This worldwide reach inspired the phrase “the empire on which the sun never sets.”

The empire developed gradually from English overseas trading posts and colonies established in the late sixteenth and early seventeenth centuries. Its expansion accelerated after Britain defeated major European rivals and gained greater control in South Asia, especially following the East India Company’s victory at Plassey in 1757.

The Mongol Empire is a frequent alternative because it was the largest contiguous land empire. The Russian Empire was also enormous, but by maximum controlled area it remained smaller than the British Empire.