How were Americans able to extend their influence to other parts of the country?

Americans extended their influence across the country primarily through westward expansion, driven by the belief in Manifest Destiny, which held that the U.S. was destined to expand its territory. This was facilitated by policies such as the Homestead Act, which encouraged settlement, and the construction of railroads that connected distant regions. Additionally, military actions and treaties often played a role in acquiring new lands, while cultural and economic initiatives helped integrate these areas into the broader national framework.