Oberlin College, where my wife and I graduated with our undergraduate degrees, has the fourth most politically liberal student body of 496 schools ranked at the website MyPlan.com based on an opportunistist non-random survey sample of 11,339 graduates of the schools in question (after Evergreen State, University of California Santa Cruz, and Bard). The college from which my brother and his wife graduated was ranked 7th most liberal. My sister-in-law's alma mater was ranked 13th. My father's alma mater was ranked 253rd most liberal out of 496. Hope College, from which my wife received some credits towards her degree, was 477th out of 496. Miami University, of Oxford, Ohio, where I grew up and took some classes was 442nd out of 496 in liberal political identity of students. CU-Boulder ranked 47th.
For what it is worth, I was reviled in some quarters while I was in college as a conservative, although of course, the political identity is relative and I was really only moderately liberal by campus standards even then. Out of about 3,000 students when I was there, Oberlin has about 600 people who were members of the campus socialists, about 40 Trotskyists, and about 8 members of the Republican club.
Oberlin has been on the frontier of progressive politics since its inception in the 1830s, at which point it was the first co-educational and the first interracial college in the country.