I know the first ones where build in Rhode Island, but I don't think that's what the answer wants :/
Under America’s first governing document, the Articles of Confederation, the national government was weak and states operated like independent countries. At the 1787 convention, delegates devised a plan for a stronger federal government with three branches—executive, legislative and judicial—along with a system of checks and balances to ensure no single branch would have too much power.
Hope this made sense!
It was the Louisiana purchase.
The answer is immigrants from northern europe
