The British Empire at its peak covered nearly a quarter of all land on Earth. The Mongol Empire was even larger — relative to the world it knew.
How to Play: Guess if the empire on the right covered a LARGER or SMALLER peak area than the one on the left.
Name A
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Top 10 Largest Empires by Peak Land Area
Historians measure empire size by peak controlled territory in millions of square kilometers. The British Empire holds the all-time record, but the Mongol Empire’s relative size — given a smaller known world — was even more dominant.
| # | Name | Peak Area (million km²) | Unit |
|---|---|---|---|
| 1 | British Empire (1920) | 35.50 | million km² |
| 2 | Mongol Empire (1270-1309) | 24 | million km² |
| 3 | Russian Empire (1895) | 22.80 | million km² |
| 4 | Soviet Union (1945) | 22.40 | million km² |
| 5 | Spanish Empire (1740-1790) | 19.40 | million km² |
| 6 | Qing Dynasty (1820) | 14.70 | million km² |
| 7 | French Colonial Empire (1920) | 13.50 | million km² |
| 8 | Abbasid Caliphate (750) | 11.10 | million km² |
| 9 | Umayyad Caliphate (720) | 11.10 | million km² |
| 10 | Yuan Dynasty (1310) | 11 | million km² |
How Empire Sizes Are Measured
Historians estimate empire size from administrative records, border treaties, and territorial maps from the period. The figures are peak land area — the maximum extent ever controlled, even briefly. They typically include vassal states and colonial possessions but not areas merely influenced.
The British Empire’s 35.5 million km² peak in 1920 included the UK itself, India, large parts of Africa, Canada, Australia, and many smaller territories. At its peak, roughly 412 million people — about 23% of the world’s population — lived under British rule. The empire began declining rapidly after WWII as colonies gained independence.
The Mongol Empire under Kublai Khan was contiguous, spanning from Korea through Eastern Europe. Its total of 24 million km² is more than twice the size of any other contiguous land empire (the second-largest contiguous empire is the Russian, at 22.8 million km²). The Mongol Empire fragmented into khanates by the 1300s.
Frequently Asked Questions
What was the largest empire in history?
The British Empire at 35.5 million km² (1920). It included the UK, India, large parts of Africa, Canada, and Australia.
Which empire had the longest reach?
The Mongol Empire (24 million km²) was the largest contiguous land empire. It stretched from Korea to Eastern Europe.
Was the Roman Empire really that small?
By modern empire-size standards yes — 5 million km² at peak. The Romans seem ‘larger’ because their territory dominated a smaller known world. Most large empires came later when geography was better understood.
Are these areas exact?
No. Historical empire sizes are estimates. Borders were often poorly mapped and shifted year to year. Modern figures (British, Russian) are more precise; ancient figures have wider error bars.
Note: Peak empire areas in million km² from historical scholarship. Pre-modern estimates carry significant uncertainty.
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