Families and friends of the new citizens waved American flags as a recording of the song "God Bless the USA" by country singer Lee Greenwood reverberated through the crowd.
"As citizens of this great country, American history is now your history," U.S. Citizenship and Immigration Services Acting Director Ken Cuccinelli told participants. "Our American future is yours to help shape. And we expect you to help shape it."
Republican President Donald Trump congratulated the new citizens, who hailed from 28 countries, in a video message.
"I didn't expect this feeling of mine. So now I'm really an American citizen — and so happy about that," said 56-year-old Ancilla Alforque Abella, a native of the Philippines.
Dahsong Kim, whose family came to the U.S. from South Korea when she was 6 years old, mixed a little pragmatism with her happiness. She noted that her friends have been saying, "Welcome to America."
But the 34-year-old attorney corrected them: "And I'm like — 'well, no, I've actually been an American this entire time.'"
The difference, she said, is that she's now an American "on paper."
"I wanted to make it known ... that immigrants are Americans too. And I hope that sort of plays out in my story in some way," she said.
Felix Maria Castillo Lachapelle, who came from the Dominican Republic, said he now will enjoy "democracy that I did not have before."
Other new citizens came from Albania, Bangladesh, Cameroon, China, Colombia, Cuba, Dominica, Guinea, Guyana, Haiti, India, Iraq, Jamaica, Kosovo, Mexico, Nepal, Nigeria, Pakistan, Romania, Russia, Trinidad and Tobago, Turkey, Ukraine, the United Kingdom and Venezuela.