Using employbl data I made an interactive map with the density of tech companies headquartered in the Bay Area.
employbl members can view the map here: https://www.employbl.com/map-of-bay-area-tech-companies
It shows a lot of companies in the south east parts of San Francisco -- this encompasses the Financial District, SoMa, Mission Bay and the Dogpatch where the Y Combinator headquarters is located.
Moving south there's another clump of companies in South San Francisco. Most of these are Biotech and Therapeutics companies..
Further south we hit Silicon Valley where there a lot of tech companies in San Mateo / Redwood City, then tons of startups and established companies in Palo Alto and Mountain View.
I'll keep iterating on this so employbl members can see exactly the companies and jobs that are available in each zip code!
Feel free to register as an employbl member today :)