The U.S lost the least land
According to me the Germans lost the most land post in WW1 because in the end the central powers were defeated by the allied powers which had been consisted of Russia Italy France England USA & Japan.
Germany!
France Russian Empire United Kingdom including colonies
Russia. :)
The Allied Powers
spain
The US did, mainly at Omaha Beach.
Greece was allied with the Allied powers. So when the Axis powers lost, then the Greeks technically won with the aid of the other allied countries.
the Allied Powers
Trade imbalance, lost jobs, lost land, losing the country.
France