What is the Bay Area?

My wife and I talk about this every once in a while, usually on a family trip, traveling outside the Bay Area. The question is simple: Where does the Bay Area begin and end?

The easiest definitive boarder is to the West. The Pacific Ocean gives us a clear Western edge to the region.

To the East, most folks would agree that Livermore, Walnut Creek, and Concord are the edge of the Bay Region and as you move towards Granite Bay and places like Tracy, you're really talking about the Central Valley.

Perhaps the most confusing parts of the question is the area to the North and the area to the South.

Let's start with the North. What's the Northern most city in the Bay Area? I would say Petaluma. My wife, Kim, would say Novato. She thinks that the small hills between Novato and Petaluma are a natural boarder to the Bay Area. I say it's Petaluma, because many people commute from Petaluma to San Francisco to work. San Francisco seems uniformally recognized as the epicenter of the Bay Area.

To the South: I would say Gilroy is still in the Bay Area, while others suggest that the Bay Area ends with the Southern most point of San Jose. Those same people would say that Morgan Hill is outside the Bay Area.

I think we really need to figure this out as a society. How can you call yourself a Bay Arean if you live in Santa Rosa? Or San Juan Bautista?