Please briefly describe the time, reasons, results and functions of the pioneering work in the western United States.

Time: From the end of 18 to the end of 19, at the beginning of the 20th century.

Reason: Slave owners in the south, land speculators and industrial capitalists in the north, usurers and ordinary people all hope to acquire land in the west.

Results: It provided superior conditions and broad market prospects for American industrialization, and also provided a broad world for the development of American agriculture, which greatly promoted the development of American economy.

In the face of all kinds of difficulties and obstacles, the American people abandoned all prejudices, overcame difficulties and forged ahead, thus cultivating and forming the American national character of seeking truth from facts, optimism and courage, which is inexhaustible wealth.

Extended data:

Immigrants came with the expansion and annexation of American territory in the middle of19th century. At that time, the territorial expansion of the United States continued in two directions: in the southwest, 1845 annexed Texas; In the 1848 US-Mexico War, it captured half of Mexico's territory; In the northwest, after long-term negotiations with Britain, a large piece of land in Oregon was acquired on 1846.

Finally, the expansion of these two aspects merged in California, completing the occupation of the whole western region. At the same time, the discovery of gold mines in California caused a rush of immigrants to the west for gold. Later, some gold diggers turned to farming or opening stores and became permanent settlers in California; The other part went from California to the northwest to explore mineral deposits.

/kloc-In 1950s and 1960s, mining camps developed into permanent residential areas because a large number of small farmers moved in to engage in food production and the area west of the Rocky Mountains was divided into some states and quasi-states.