EO Operational Requirements: Obtaining Copies of Exemption Determination Letter from IRS
How can I get a copy of my organization's exemption letter?
You may request an affirmation letter. The affirmation letter serves the same purpose for grantors and contributors as the original determination letter.
If the affirmation letter will not meet your needs and you wish to obtain a copy of the original determination letter, you must send a written request to the EO Determinations office in Cincinnati. The request should be submitted using Form 4506-A, or in a letter containing the name and employer identification number of the organization along with the name, address, and phone number of the requester. Securing a copy of the original determination letter to send to you may take up to 60 days or longer.
As discussed in Publication 4573, Group Exemptions, subordinate organizations under group exemption rulings should contact the central organization that holds the group ruling to obtain confirmation of their status as members of the group.