Inspired by the ideology of Manifest Destiny, which held that European Americans were divinely ordained to settle the whole of the North American continent, white settlers pushed ever further westward towards the Pacific. As they did so, they increasingly came into violent conflict with Native American Indians over land and natural resources, especially after the discovery of gold in western territories sparked the Gold Rush. Prospective gold-diggers flooded into the Rocky Mountains and Pacific Northwest, clashing—sometimes violently—with the Native Americans they encountered there. By 1890, the U.S. Census officially declared the frontier "closed."