The final field for The US Open is not known until the final rounds of US qualifying held on 4th June
Pros exempt qualifying as follows:

Key to Player Exemptions

1. Winners of the U.S. Open Championship the last 10 years (2002-11)

2. Winner and runner-up of the previous years U.S. Amateur Championship (must be an amateur)

3. Winner of the previous years British Amateur Championship

4. Winner of the previous years Mark H. McCormack Medal (top-ranked in WAGR & must be an amateur)

5. Winners of the Masters Tournament the last five years (2008-12)

6. Winners of the British Open Championship the last five years (2007-11)

7. Winners of the PGA of America Championship the last five years (2007-11)

8. Winner of the Players Championship the last three years (2010-12)

9. Winner of the current years European Tour BMW PGA Championship

10. Winner of the previous years U.S. Senior Open Championship

11. From the previous years U.S. Open Championship, the ten lowest scorers and anyone tying for 10th place

12. Those players who qualified for the previous years season-ending  Tour Championship

13. Top 60 point leaders and ties from the current World Rankings as of May 21, in current year

14. Top 60 point leaders and ties from the current World Rankings as of June 11, in current year

15. Special exemptions selected by the USGA