Han Dynasty....
Largest empire
All empires (brackets shows the date when the empire was at its largest and/or the ruler)
British Empire - 36.6 million km²[1] (under King George V in 1921) (excludes Antarctic territorial claims)
Mongol Empire - 33.2 million km²[1] (under Khublai Khan in 1279) (excludes Northern Siberia)
Russian Empire - 22.8 million km²[2][3]) (under Nicholas II in 1895)
Spanish Empire - 19 million km²[1] (under King Charles III)
Arab Empire - 13.2 million km²[1] (under the Umayyad Caliph Al-Walid I)
Qing Empire - 12 million km²[4] (under Emperor Qianlong)
French Empire - 12 million km²[1]
Portuguese Empire - 10.4 million km²[1]
American Empire - 10 million km² [5] (1898-1902 and 1906-1908)
Achaemenid Persian Empire - 7.5 million km²[6] (under Darius the Great)
Japanese Empire - 7.4 million km²[1] (during World War II)
Ming Empire - 6.5 million km²[2]
Han Empire - 6 million km²[2]
Ottoman Empire - 5.6 million km²[1]
Roman Empire - 5.6 million km²[1] (under Emperor Trajan)
Tang Empire - 5.4 million km²[2] (under Emperor Gaozong of Tang[7])
Macedonian Empire - 5.4 million km²[1] (under Alexander the Great)
Maurya Empire - 5 million km²[2] (under Ashoka the Great)
Mexican Empire - 4.7 million km²[1]
Timurid Empire - 4.4 million km²[2]
Mughal Empire - 4 million km²[2] (under Aurangzeb)
Hunnic Empire - 4 million km²[2] (under Attila the Hun)
Seljuq Empire - 3.9 million km²[2]
Seleucid Empire - 3.9 million km²[1]
Italian Empire - 3.8 million km² (during World War II)
Dutch Empire - 3.7 million km²[1]
Nazi German Empire - 3.6 million km²[1] (during World War II)
Gupta Empire - 3.5 million km²[2] (under Chandragupta II)
Sassanid Persian Empire - 3.5 million km²[2] (under Khosrau I)
Ghaznavid Empire - 3.4 million km²[2]
Pala Empire - 3.2 million km²[8] (under Devapala)
Delhi Sultanate - 3.2 million km²[2]
Khazar Empire - 3 million km²[2]
Median Empire - 2.8 million km²[2]
Byzantine Empire - 2.7 million km²[2]
Chola Empire - 2.6 million km²[9] (under Rajendra Chola I)
Belgian Empire - 2.5 million km²[2]
Inca Empire - 2 million km²[2]
Majapahit Empire - 1.5 million km²[10]
Neo-Assyrian Empire - 1.4 million km²[2]
Aksumite Empire - 1.3 million km²[2]
Srivijaya Empire - 1.2 million km²[2]
Frankish Empire - 1.2 million km²[2]
Harsha Empire - 1 million km²[2] (under Harsha Vardhana)
Egyptian Empire - 1 million km²[2]
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Largest ancient empires
Achaemenid Persian Empire - 7.5 million km² (under Darius the Great)
Han Empire - 6 million km²
Roman Empire - 5.6 million km² (under Emperor Trajan)
Macedonian Empire - 5.4 million km² (under Alexander the Great)
Maurya Empire - 5 million km² (under Ashoka the Great)
Hunnic Empire - 4 million km² (under Attila the Hun)
Seleucid Empire - 3.9 million km²
Gupta Empire - 3.5 million km² (under Chandragupta II)
Sassanid Persian Empire - 3.5 million km² (under Khosrau I)
Median Empire - 2.8 million km²
Neo-Assyrian Empire - 1.4 million km²
Aksumite Empire - 1.3 million km²
Egyptian Empire - 1 million km²
Akkadian Empire - 650,000 km²
Nanda Empire - 600,000 km²
Neo-Babylonian Empire - 500,000 km²
wikipedia.org
The Mongol Empire wasn't ancient.