Westward Expansion refers to the period in the 19th century when the United States expanded its territory westward across North America. This movement was driven by the belief in Manifest Destiny, the idea that Americans were destined to spread across the continent. Key events during this time included the Louisiana Purchase in 1803 and the California Gold Rush in 1849, which attracted many settlers seeking new opportunities. The expansion led to the establishment of new states and territories, 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 regions.