Which country did Napoleon invade in 1812 that led to his downfall? He invaded Russia. Napoleon’s Russian campaign began on 24 June 1812, when the multinational Grande Armée crossed the Neman River into the Russian Empire.
Napoleon hoped to force Tsar Alexander I to resume cooperation with the Continental System, an economic blockade designed to isolate Britain. Instead of offering a decisive battle early in the campaign, Russian armies retreated eastward, denying the French a quick victory and stretching their supply lines across enormous distances.
The French captured Moscow after the Battle of Borodino, but the city could not provide the supplies or peace settlement Napoleon needed. A devastating retreat began in October. Cold weather, hunger, disease, exhaustion and repeated attacks destroyed much of the army as it crossed the Berezina River. Napoleon’s weakened position encouraged European powers to unite against him, leading to his defeat in 1813 and eventual abdication in 1814.