the current western United States is geographically dominated the Central Valley, one of the most fertile valleys in the world. OTL it comprises 160,000 sqkm and dominates the state of California. For reference here is a picture of the Central Valley compared to the Japanese Home Islands:
With a POD during the Spanish colonial era, make this Central Valley become an early population center, comparable to population centers in Japan or other parts of the Old World. Bonus points if they become more populous than New England by present day without major war or famine affecting population growth.
With a POD during the Spanish colonial era, make this Central Valley become an early population center, comparable to population centers in Japan or other parts of the Old World. Bonus points if they become more populous than New England by present day without major war or famine affecting population growth.