(March 3, 1800 – August 10, 1886)[1] was an American Presbyterian clergyman and educator who served as the tenth President of Princeton University, then known as the College of New Jersey.

Maclean also shifted his professorship from mathematics to ancient languages until 1854, when he succeeded James Carnahan as the tenth president of the university.

In 1855, after Nassau Hall burned down, he sought the financial support of alumni and beneficiaries to contribute funds for rebuilding.

He operated the college on a limited budget for five years and gave up part of his own salary to help rebuild the hall.

The university lost a number of students who joined the Union and Confederate armies during the Civil War.

Maclean kept the faculty together and managed a complete educational program for the students still attending the university.

During the war Maclean, as voted by the board of trustees, conveyed an honorary Doctor of Laws degree to President Abraham Lincoln.

Lincoln accepted, and wrote to Maclean that "[t]he assurance conveyed by this high compliment that the course of the government which I represent has received the approval of a body of gentlemen of such character and intelligence in this time of public trial is most grateful to me."

As a member of the New Jersey Prison Association, he conducted weekly services at the state penitentiary in Trenton.