Princeton sits atop the rankings for best colleges yet again.

For the ninth straight year, Princeton University was named the No. 1 college among national universities, and Williams College was named No. 1 among national liberal arts schools for the 17th year in a row, according to the latest ranking from U.S. News & World Report.

Every year, the news outlet publishes what many regard as the gold standard for college rankings in the United States. This year, the outlet looked at 1,400 colleges and universities focusing on academic quality and measures such as graduation rates, retention rates and social mobility.

Graduation rates for first-generation college students were factored into the ranking's overall methodology for the first time this year, U.S. News said.

U.S. News also added a new ranking this year: Top Performers on Social Mobility.

The new ranking "evaluates which schools best serve underrepresented students" and analyzes enrollment and graduation rates of low-income students with Pell Grants as a proxy.

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"For more than three decades, we've collected and analyzed data on thousands of colleges and universities across the country and helped put schools on the map," said Kim Castro, editor and chief content officer of U.S. News. "We've found the best institutions to be ones committed to academically and financially supporting their students through graduation. They draw in high-quality professors and set students up for postgraduate success."

Here's a look at the rankings:

Top Colleges Overall

National Universities – Top 3

1. Princeton University (NJ)

2. Harvard University (MA)

3. Columbia University (NY) (tie)

3. Massachusetts Institute of Technology (tie)

3. Yale University (CT) (tie)

National Liberal Arts Colleges – Top 3

1. Williams College (MA)

2. Amherst College (MA)

3. Swarthmore College (PA) (tie)

3. Wellesley College (MA) (tie)

Top Public Schools

National Universities – Top 3

1. University of California—Los Angeles

2. University of California—Berkeley

3. University of Michigan—Ann Arbor

National Liberal Arts Colleges – Top 3

1. United States Naval Academy (MD)

2. United States Military Academy (NY)

3. United States Air Force Academy (CO)

Top Performers on Social Mobility

National Universities – Top 3

1. University of California—Riverside

2. University of California—Santa Cruz

3. University of California—Irvine

National Liberal Arts Colleges – Top 3

1. Cornell College (IA)

2. Agnes Scott College (GA)

3. Houghton College (NY)

Follow USA TODAY's Ryan Miller on Twitter: @RyanW_Miller