Hawkette, Michighan has a HUGE Northeastern/Mid Atlantic student population, both in the absolute and in the relative sense. There are currently over 3,500 (out of 25,000) undergrads from the Northeast/Mid Altlantic. Three thousand five hundred undergrads is more than what many elite Northeastern/Mid Atlantic colleges enroll! I cannot overstate how massive 3,500 is. Even in relative terms, that's 14% of Michigan's undergraduate population. The most diverse private universities outside of the Northeast/Mid-Atlantic don't have more than 25% of their undergrads hail from the Northeast.
New York: 1,355
New Jersey: 664
Pennsylvania: 386
Maryland: 361
Massachusetts: 250
Connecticut: 205
New Hampshire: 27
Vermont: 18
Maine: 16
Rhode Island: 11
TOTAL: 3,508
http://www.umich.edu/~regoff/report/07fa115.pdf
I don't think you will find a single university outside of the Northeast/Mid Atlnatic that has a larger NE/Mid-Atlantic undergraduate population.