TV Latest said Fakih, 24, a Lebanese-American born in New York, was among 51 beauties vying for the highly contested honour.
She beat first runner-up Miss Oklahoma, followed by Miss Virginia, Miss Colorado and Miss Maine.
The competition aired live to US viewers on NBC.
The network owns the pageant with celebrity entrepreneur Donald Trump.
Fakih will represent the US at the 2010 Miss Universe pageant later this year.
Arab Americans across metro Detroit cheered as Rima Fakih of Dearborn was crowned Miss USA tonight in Las Vegas.
“This is unbelievable,” said Rami Haddad, 26 of Livonia, one of Fakih’s biggest supporters. “It’s a dream come true. I can’t express my feelings.”
Fakih, of Lebanese descent, is believed to be the first Arab American and Muslim to become Miss USA.
• Miss Michigan shows Arabs' diversity
She is also the first Michigander to be Miss USA since 1993.
“This is great news for Michigan,” said Haddad. “We have beauty here. We have talent.”
Haddad said Fakih’s win can help motivate Michiganders to dream big.
“This will motivate us,” Haddad said. “She was so determined.”
“This is historic,” Imad Hamad, regional director of the American-Arab Anti-Discrimination Committee, said. “This shows the greatness of America, how everyone can have a chance to make it.”
Supporters are gathering at La Pita in Dearborn for a party to celebrate Fakih’s win.
The contestants took the stage tonight at Las Vegas' Planet Hollywood Resort & Casino to compete for the crown and the opportunity for a place in the Miss Universe pageant.
The 24-year-old brunette from Michigan beat out four blondes and 46 other women for the 2010 Miss USA title after nearly stumbling in her evening gown.
Fakih won the pageant Sunday night after swimsuit, evening gown and interview competitions.
During the competition, Fakih nearly fell while finishing her walk in a long, strapless gown because of the length of its train, but she recovered without a spill and went on to win.
