Students gather for a fall 2018 event at the University of California at Riverside. (Stuart W. Palley for The Washington Post)

If it is early September, it must be college ranking season. Therefore, it must be the time of year that U.S. News & World Report will proclaim Princeton University and Williams College the top schools in the country.

Which is once again the conclusion of lists U.S. News released Monday.

For the ninth straight year, Princeton was the No. 1 national university, according to U.S. News. It was followed by Harvard University and three schools in a three-way tie for third: Columbia University, Massachusetts Institute of Technology and Yale University.

Williams was deemed the top liberal arts college for the 17th straight year, followed by Amherst College and, tied for third, Swarthmore and Wellesley colleges.

Among universities in the District of Columbia, Georgetown ranked 24th (down from 22nd last year). George Washington ranked 70th (down from 63rd), American University 77th (up from 78th), Howard University 104th (down from 89th) and Catholic University 139th (down from 129th). Gallaudet University debuted on the national list at 179th. Among public flagships in the Washington region, the University of Virginia ranked 28th (down from 25th) and the University of Maryland 64th (down from 63rd).

U.S. News has drawn notice for decades for ranking colleges based on a subjective and controversial formula. It draws from data on graduation rates, social mobility, faculty resources, financial resources, standardized admission test scores, alumni giving rates and the results of peer assessment surveys. Critics say the rankings are more about prestige and wealth than educational values that matter. But the lists still hold influence among consumers and higher education leaders.

In recent years, rankings have proliferated from other sources, including Money, Forbes, Washington Monthly and a joint venture of the Wall Street Journal/Times Higher Education.

To add a wrinkle to the parlor game, U.S. News created a list this year that it calls “top performers on social mobility.”

That analysis uses data on Pell Grants to examine enrollment and graduation rates of students from low-income families. U.S. News ranked three University of California schools best among national universities on this score: UC-Riverside first, UC-Santa Cruz second and UC-Irvine third. Tied for fourth were University of La Verne, Howard university and Rutgers University-Newark.

Liberal arts colleges leading the analysis for social mobility were Cornell College — which is in Iowa, separate from and slightly older than the Ivy League university of the same name in New York — followed by Agnes Scott College and Houghton College.