<p>I think you need to write the letter to your regional admission officer He or she is the one who will advocate for you at the admission commitee. You could send it to both, but you should definitely send it to your regional admission officer.</p>
<p>jerseygirl07 - There are no regional admission officers for Princeton. I would write a letter to the Dean of Admissions indicating that you were disappointed that you were deferred and that Princeton is your first choice and that you hope to be accepted. I would include any updates</p>
<p>Take a quick look around on some of the boards and you might get ideas for your letter. When ED/EA letters came out in December, there were a lot of threads started by deferred students.</p>