Yeah, fascinating looking at the "San Francisco" one. Closest I can get to its numbers are San Francisco, Marin, Contra Costa, Alameda, and San Mateo counties, which makes some sense, excluding Santa Clara (where San Jose is), and the further outlying counties. But the "Bay Area" is generally considered the nine counties that have bayfront property (pop. ~$7.5M; including the five I listed above, plus Santa Clara, Sonoma, Napa, and Solano). San Francisco itself is a "small" big city, pop ~850,000; 4th largest in California, behind LA, San Diego, and San Jose.