Princeton slips to No. 2, ending eight straight years of at least sharing the top ranking. The latest edition hits newsstands Monday, but was to be published Friday on the magazine's Web site.
Yale follows at No. 3, and MIT and Stanford tie for fourth. The University of California, Berkeley is the highest-ranked public university, at No. 21 overall. In a separate list for liberal arts colleges, Amherst moves up one spot to tie Williams, its rival just up the road in Massachusetts, for the top spot.
In an e-mailed statement, Harvard Faculty of Arts and Sciences spokesman Robert Mitchell said that "it is always nice to be recognized in this way. However, our admissions officers always tell prospective students that they should select a college or university that best suits their needs, not by its position in a ranking."
The ranking formula takes account of factors such as SAT scores, peer reputation, selectivity and alumni giving.
So how did Harvard edge past its Ivy League rival? A comparison of last year's numbers points to one category where it moved ahead of Princeton - average class size. Harvard reports the percentage of students in classes under 20 students rose from 69 percent to 75 percent since last year's report, while the percentage in classes bigger than 50 fell from 13 percent to 9 percent.
Asked whether Harvard had made a particular effort to reduce class sizes, Mitchell said: "We have worked and will continue to work very hard to enhance the academic experience for undergraduate students." Since 2000, he said, Harvard has added 86 freshman seminars (which have fewer than 12 students), and more than 100 tenure-track faculty, while its student body size has stayed about the same.
While U.S. News' often-criticized but closely followed traditional rankings typically get most of the most attention, they rarely change much from year to year. So the magazine has been adding new lists to keep things interesting.
Debuting this year are rankings identifying "Up and Comers" - innovative institutions that college officials identify as poised to move up in the rankings in the coming years. Topping that list are George Mason University in Virginia, Clemson in South Carolina, the University of Southern California and Arizona State.
"One of the criticisms of the rankings is that they move very slowly, it takes a long time for schools to improve," said Brian Kelly, the magazine's editor. "They may be doing things today that aren't going to be reflected for five years in the rankings. We wanted to find a way to illuminate some schools that are doing some really interesting thing."
Also new this year are rankings based on a survey of high school guidance counselors, a group that has often criticized the magazine's mathematical formula.
The survey was sent to counselors at about 1,600 high schools, and about one-quarter responded. Respondents put many of the same schools at the very top of the list, with Harvard, MIT, Princeton and Yale tying for first in their survey. But a number of schools do better in the counselors' survey than in the traditional rankings. For instance, Cornell and Brown universities were 14th and 16th, respectively, in the main rankings but tied for fifth with the counselors.
The U.S. News rankings remain the best-known but have spawned a range of competitors. The latest include Forbes.com, which published its first-ever rankings this month, focusing on student achievement and ranking Princeton at the top.
A big theme this year is the environment. This year's college guide from Princeton Review (not affiliated with the university) includes a new category of "green ratings" for colleges. The National Wildlife Federation this week put out a campus environmental report card that doesn't rank campuses but highlights ones with policies it considers exemplary.