Although Facebook has a reputation of being college-elitist, Google and other larger companies are much less so, in that they recruit widely, due to greater recruiting resources and needs. There may be some correlation to college prestige at some companies, but may be due to higher standards in technical interviews being more likely to be met by those who were able to get admitted to more prestigious colleges, not because those from lower prestige colleges were excluded.
For smaller companies, there is an advantage to being nearby, because travel recruiting is less convenient for a companies that needs only a few new employees.