I am on the board for a nonprofit organization. I would like to see
the list of donors from our last fundraiser to thank those donors whom
we know gave on our behalf. Is the list of donors a privacy protected
list or is it public information? The organization does publish a list
in its quarterly newsletters which go out to about 1600 people and
businesses.

Even though the organization has already sent a thank you to all
donors, we feel that people who know us and have given on our behalf
deserve a more personal thank you. The CEO does not want to allow us
to have access to the list for privacy reasons.

I would like to know the process as it should be followed and to know
how other organizations handle such cases.

What does the org's privacy policy say?

Write your thank you letters and ask the 501(c)3 to mail them for you.
Be prepared to pay the postage.