Why did the United States want new acquisitions in the West?

Answer:United States' territory is any extent of region under the sovereign jurisdiction of the federal government of the United States,[1] including all waters (around islands or continental tracts) and all U. S. naval vessels.[2] The United States asserts sovereign rights for exploring, exploiting, conserving, and managing its territory.[3] This extent of territory is all the area belonging to, and under the dominion of, the United States federal government (which includes tracts lying at a distance from the country) for administrative and other purposes.[1] The United States' total territory includes a subset of political divisions.