Age of Empires III: Definitive Edition – United States Civilization DLC (PC) Steam Key is an expansion that introduces the United States as a full-fledged, playable civilization to the game for the first time. This expansion opens a new chapter in the history of the series, offering a unique approach to empire development, fresh civilization advancement mechanics, and all-new units, buildings, and technologies. It's the perfect choice for players who like flexibility, dynamic gameplay, and a variety of strategic options. A New Civilization – The United States The United States is a faction that stands out for its innovative development system and great versatility. With a combination of advanced economy, strong ranged units, and unique political mechanics, Americans are able to adapt to any situation on the battlefield.