This document traces the history of American expansion on the west coast of North America from the 15th century arrival of Europeans to the mid-19th century. Key events included Spanish exploration and settlement of California in the late 18th century, Mexico gaining independence from Spain in 1823 and governing California, and the United States defeating Mexico and acquiring California and other territories in 1846. The document also discusses the concepts of manifest destiny and American control over natural resources that drove further expansion.