The Mill Hill School Foundation is an approved institution with the British Schools & Universities Foundation (BSUF). BSUF was set up over 40 years ago to support British schools and universities in a tax efficient way.
To make a gift and take a U.S. income tax deduction, you may make a donation to the British Schools & Universities Foundation (Federal I.D. Number 13-616-1189), a charitable organization approved by the U.S. Internal Revenue Service under Section 501(c)(3) of their Code.
The Mill Hill School Foundation has a US representative for BSUF, Mike Finlay (Weymouth 1955-58). If you would like to make contact with Mike please email appeal@millhill.org.uk.
If you would like to make a donation by check, download a Donor Transmittal Form 
and send it to:
British Schools and Universities Foundation
575 Madison Avenue
Suite 1006
New York
NY 10022-2511
A preference for Mill Hill School Foundation should be expressed on the transmittal form not on your check which is to be drawn to the order of the British Schools & Universities Foundation. Such preferences are respected by the Foundation but all grants are made at its sole discretion, as required by the I.R.S. BSUF will send you a receipt. If you wish the tax deduction in the current year, you should send your gift no later than four weeks before December 31st.
You can make one-time or regular donations by credit card using the Network for Good. Just follow the instructions on the BSUF website.
A provision may be made in your Will or Trust bequeathing money to the BSUF. To contact BSUF regarding a bequest please send an e-mail to treasurer@bsuf.org.
Why not consider setting up a Charitable Remainder Unitrust or an Individual Retirement Account or giving securities. You can find more information on the BSUF website.