The 101, 880, and 237 freeways.

"The Golden Triangle"

It's the "sacred triangle" you may savor upon my impending visit
to the East Bay Area 9th---?  
In all seriousness, I always thought it encompassed parts of the Arena,
as well as the college area of East Palo Alto?
When I resided in the Orinda area of The East Bay,
we called the LamOrinda  Area which encompasses Orinda, Moraga, Lafayette, and  
a sliver of Walnut Creek as "The Golden Triangle" as well!