It’s back-to-school season, and as college students get ready to move into their dorms, some might be wondering about campus culture—including whether their school is marijuana friendly. The Princeton Review is here to help. Besides ranking colleges overall each year, it also includes breakout sections offering ratings on a wide range of college features. For this year’s issue, the review guide looked at the top 20 universities where students use cannabis the most and least. To compile the list, released earlier this week, Princeton Review asked 140,000 students at 385 schools a simple question: “How widely is marijuana used at your school?” The results, for the most part, aren’t especially shocking. In general, marijuana is consumed most frequently at colleges located in states with looser cannabis laws, or more libertarian climates. Students are least likely to consume cannabis, according to the rankings, if they attend religious or military schools, or if the campuses are located...