How did the united states change between 1776 and 1870

During these time many things happened to the U.S such as the declaration of independence, starting of thanksgiving, civil war, during the civil war the U.S had learned so many things such as new strategies, better ways to use guns and cannons. 

The transcontinental railroad provided a means of fast transportation. it cut a 6 month trip into 6 days, created jobs for many people and encouraged immigration. the homestead act played a huge role in western expansion; it allowed settlers to begin a fresh start, and gave them land in exchange for their residence for up to five years and a small fee.