Delta Upsilon (
ΔΥ) is the seventh oldest extant, all-male, college Greek-letter organization in North America. Founded on November 4, 1834, at
Williams College in
Williamstown, Massachusetts, it is popularly and informally known as "Delta U" or "DU" and its members sometimes called "DUs". Though historically set at
New England private universities, as of 2012 it had 76 chapters across the United States and Canada. A number of its buildings are listed on the
National Register of Historic Places.