What was America's greatest land victory after a war. (No specific war)?

Answer 1

The Mexican American War, which was basically theft by the U.S. (before the Alamo, which was in Mexico, the U.S. government was already chaging the boarders). With little loss of life, the U.S. got about 1/3 of the U.S. land.

Answer 2

Wasn't a War,, But he Louisiana Purchase was a steal,, or in this case a victory!