Complex sentence: The first to hear confirmed information of the California Gold Rush were the people in Oregon, the Sandwich Islands (Hawaii), Mexico, Peru and Chile and they were the first to start flocking to the state in late 1848.
Split into simpler sentences: The first to hear confirmed information of the California Gold Rush were the people in Oregon, the Sandwich Islands (Hawaii), Mexico, Peru, and Chile. They were the first to start flocking to the state in late 1848.