What was the gold rush?

The California Gold Rush was sparked by the discovery of gold nuggets in the Sacramento Valley in[1] 1848, leading to a population boom in the territory and the extraction of $2 billion worth of precious metal[1]. It led to a surge of migrants, known as the '49ers, who traveled to California in search of wealth, leading to the state's rapid admission to the Union. The environmental impact of the Gold Rush altered the landscape of California[1] and led to the dominance of the agriculture industry in the state.

[1] history.com