Before Americans
The first people to enjoy the coast, mountains, and valleys of California are believed to have come from Siberia as long as 30,000 years ago. At the end of the last Ice Age, bands of nomadic hunters with their families crossed the land bridge at what is now the Bering Strait. Those hundreds or at most, thousands of men and women spread throughout North and South America to form the rich mosaic of native peoples who met the first European explorers.

No one knows when the first native peoples moved into what is now California. But by the time of Columbus' rediscovery of North America (for the continent had been "discovered" many times before), between 100,000 and 200,000 Native Americans of many different tribal groups lived here.

For the next three-and-a-half centuries Spain, England, and Russia claimed parts of the western edge of North America. Spain's presence was strongest, anchored by the series of Franciscan missions and settlements stretching from San Diego on the south to the San Francisco Bay region on the north.

This meant that by the time of American independence, California was sparsely settled but well-known, with active sea-borne commerce to Asia, South America, the East Coast, and Europe. People of many different ethnic heritages created a distinctive culture as they farmed, raised cattle, fished, and established California's ports and its agricultural economy.

United States Interest
When the United States first became interested in acquiring "Alta California" in the 1820s, the idea of "Manifest destiny" a continental nation stretching from sea to sea was beginning to be discussed seriously. In a few decades, the country had grown from thirteen small, Atlantic coast colonies into a land so vast that no one even knew for certain where its boundaries lay.

As Americans began settling the huge expanses of the Louisiana Purchase, they also moved increasingly into California. The California Trail, Spanish Trail, and Desert Trail led optimistic pioneers west to the coast in the 1830s and 1840s.

Change came quickly in those decades; first independence from Spain in 1825 as part of the Mexican Republic, and then status as a U.S. Territory after the Mexican War of 1846-1848. In between, there was a short-lived California Republic, political intrigue as the U.S. maneuvered to acquire the region in any way it could, and the lingering effects of British and Russian colonization to the north.

The population of California was equally fluid, with fortune seekers mixing with long-established families and newcomers pushing the frontier ever eastward. There was conflict between individuals and people of differing ethnic backgrounds. But the real struggle involved the creation of an entirely new civilization far from the established market and industries of the East or of Europe.

By the mid-19th century, Americans realized that arrayed before them was a land so rich in natural resources and so promising to a restless populace that "California or Bust" meant a trip to the promised land. Those who made it found plenty of opportunity. The call of California was powerful even before the discovery of gold.

This land was neither empty, nor unknown, 150 years ago. It was distant, mythical, raw, and energized by the prospects of settlement and prosperity. But it also had been shaped by longtime Spanish and Mexican colonization, 300 years of exploration, and a Native American presence extending back thousands of years.