What were some rewards of the westward expansion?

It helped complete the idea of America's Maniest Destiny, expanding from sea to shining sea. It also provided valuable farming land for the growing population to settle, and once they got to California they disccovered Gold and the Gold Rush began. It also helped address theissue of slavery in the Us, depending on whether or not each new state that was exapnaded into was declared to be a free or slave state, and in turn sending a delegation to the American Congress to fight for the chosen set up.