James McMahon (Apr. 22, 1856 – June 1, 1922) of Ithaca, New York was an American educator, mathematician and early American proponent of professionalization in the teaching of advanced mathematics. A professor and Chairman of the Mathematics Department in Cornell University’s College of Arts & Sciences, McMahon was a founding member of the American Mathematical Society (as the predecessor New York Mathematical Society) in 1891. For seven years he served as associate editor of the Annals of Mathematics. He was also the American Association for the Advancement of Science’s Secretary (1897), Section A (Mathematics and Astronomy); General Secretary (1898), and Vice-President (1901). McMahon was also featured in the publication, American Men (and Women) of Science.