The Harvard Crimson just published a piece on where the Harvard class of 2018 is going after graduation.
22% of them are going to New York (state I believe), 20% to Massachusetts, and 15% to California. The next biggest destination is Washington, DC at 4.9% (District of Columbia only?)
Another 9.1% are going international and 7.3% are undecided on where to go.
Add these numbers up and we see that 57% of Harvard grads are in NY, MA, or CA.
We also see that less than 22% of graduates definitively chose a US location other than NY, MA, CA, and DC.
Here’s the Crimson’s map, which doesn’t fully show the degree of concentration, but is interesting nevertheless.