The First American to be mentioned in a Prenumeranten - 1787 Berlin

What appears to be the earliest American mentioned in a prenumeranten (Prenumeranten is a Yiddish term meaning “prior numbers.” It refers to people who pre-subscribed or ordered copies of a book before its publication), shows up in Hashorashim, by Isaac Satanow (1733-1805). On page 4 of the first volume, appears a lengthy list of prenumeranten for Hashorashim and Sefer Hamichlol which he published and among the many names, appears ר יהודא בר"א ובנו באמעריקא.
There is also one prior mention of a Jew from Jamaica in a book printed in London in 1780, but this appears to be the first from a Jew in the newly declared United States.

Title page of the Sefer Hashorashim, 1787 Berlin.

ר יהודא בר"א ובנו באמעריקא appear right in the middle of the third column

Hat-tip" Dr. S. Sprecher