American westward expansion

American westward expansion was the 19th-century movement of settlers and pioneers from the eastern United States toward the western territories. Driven by the belief in Manifest Destiny—the idea that Americans were destined to spread across the continent—it involved acquiring land through treaties, purchases, and sometimes conflict, such as the Mexican-American War. This expansion facilitated economic growth, settlement, and development of new states, but also led to displacement and hardships for Native American tribes. Key events include the Louisiana Purchase, Lewis and Clark’s expedition, the Oregon Trail, and the California Gold Rush, shaping the nation’s growth and geography.