Smith College (all female). According to Hillel International College Guide, 9% Jewish students. Great academics. member of Five College Consortium, with Hampshire, Mount Holyoke, Amherst, and U Mass Amherst. Northampton is a great college town.
According to same source, Vassar College has 21% Jewish students, Bard College 15%, Franklin & Marshall 13%, Union College 13% (very strong in sciences), Connecticut College 8%.
Good luck!