Settlement of the American West helped to fulfill the idea of Manifest Destiny. Through advancements in technology, we were able to improve farming and transportation. This allowed farms to develop in the Great Plains and they were able to ship grains and meats to the rest of the world.
With the completion of the Transcontinental Railroad, people and goods could now be transported across the United States. Boom Towns popped up where valuable ore was discovered and mining provided wealth.
The fertile farmland of the west and the ability to transport goods to market on the railroad led to the cattle kingdom developing. Cities like Chicago grew as ranchers sent the cattle to market. Freedmen found opportunity in the west as cowboys. The Vaqueros skills proved to be crucial to the ranch owners.