John Blair (1720 – December 8, 1771) was a Presbyterian minister, a Trustee, Professor, and Acting President of Princeton University.
His nephew, Samuel Blair was the second Chaplain of the United States House of Representatives.
He was educated in under the Reverend William Tennent at the Log College,[1] the first theological seminary serving Presbyterians in North America located in what is now Warminster, Pennsylvania (then known as Neshaminy).
[1] He then moved to Londonderry Township where his brother, Samuel Blair had founded the Faggs Manor Presbyterian church and associated classical school.
[2][1] As the funds to support the Professorship were insufficient, and Witherspoon was able to teach and lead the college, it was agreed that Blair would resign as Professor.