Yes, we did. We built every aspect of it. After mapping it, we settled it, created the settlements and cities, and explored from there. We bought and conquered more territory. We fought the wars, died and bleed to build this country. We innovated and invented things that improved settlements and life for us and everyone else. We built the roads, highways, and railroads. We raised the skyscrapers and churches. We created the political systems that make this country great. We did literally everything. We constituted the vast majority of people here. So yes, we built America in every way.