The incoming and outgoing professional correspondence of Mark Jefferson date between 1875-1949. The scope of the correspondence covers a wide range of topics and notable professionals in the field of geography. The correspondence includes his time as a teacher and administrator for the Massachusetts Public School system, his time at Harvard University, and his teaching career at Michigan State Normal College. Such notable names in the collection include prominent geographers William Morris Davis, Isaiah Bowman, and many MSNC faculty and staff. Jefferson and Isaiah Bowman often corresponded when suggesting book and article ideas or content. Jefferson also received quite a few requests to quote his works in books and articles. One request is from 1913, in which Ellsworth Huntington from Yale University asked to take some of Jefferson's "incorrect comments from a recent publication" to compare with his own findings. The gracious Jefferson promptly gave permission to Ellsworth, eager to read his own findings.
The collection also includes local projects that Jefferson was a part of including the Ypsilanti Water Project, notes on his works submitted for publication, correspondence with book publishers, textbook recommendations, requests for speaking engagements, and his travel plans for work in the field.