Yeah, but there are currently only 284 million in the US, which means that the Salton Sea *region* could cover US needs easily, and by itself.

We already have brine and lithium extraction and geothermal projects in the region.

Here's a DOE report on the subject.

https://www.energy.gov/eere/articles/us-department-energy-analysis-confirms-californias-salton-sea-region-be-rich-domestic