American Westward Expansion refers to the period in the 19th century when settlers moved westward across the United States. This movement was driven by the belief in Manifest Destiny, the idea that Americans were destined to expand across the continent. Key events included the Louisiana Purchase in 1803 and the California Gold Rush in 1849, which attracted many people seeking new opportunities. The expansion led to the establishment of new territories and states, as well as conflicts with Indigenous peoples. The construction of railroads, such as the Transcontinental Railroad, facilitated travel and trade, further promoting settlement in the Western United States.