Of the 127 people who were arrested in the northeast U.S. alone, U.S. Attorney General Eric Holder said 91 are suspected members or associates of La Cosa Nostra families, including 30 "made men" -- who are "among the most dangerous criminals in the country." The FBI also sent agents overseas to assist the Italian police in the arrest of a single suspect there.
The other 36 defendants were charged for "their roles in alleged associated criminal activity," a statement from the Department of Justice said.
Holder, who traveled to New York to make the arrest announcement, said the operation was an "unprecedented collaboration" between four U.S. attorney offices, the FBI and various federal, state and local authorities. The massive take down was pulled off without a single incident, Fedarcyk said.
"This largest single day operation against La Cosa Nostra sends the message that our fight against traditional organized crime is strong, and our commitment is unwavering," Holder said in a statement.
In the operation, dubbed "Mafia Takedown" by the FBI, six major players were arrested in addition to more colorfully-named smaller fish like Vincenzo "Vinny Carwash" Frogiero, Frank "Meatball" Ballantoni, Anthino "Hootie" Russo, John "Johnny Bandana" Brancaccio and Michael "Jello" Kutenia were also arrested, according to court documents.
CLICK HERE to see a slideshow of the country's most notorious gangsters.
"We have charged mob bosses and mob associates alike," Holder said Thursday. "Today's successful arrests across multiple cities and involving multiple mafia families sends a clear message that in our fight against organized crime, the Justice Department is targeting federal resources and working with our state and local law enforcement partners like never before..."
"We are committed and we are determined to eradicate these criminal enterprises," he said.
The charges vary from labor racketeering, narcotics trafficking and extortion to murder. Some of the cases reach back 30 years.
"Their alleged crimes include numerous violent and illegal acts," Holder said. "Some allegations involve classic mob hits to eliminate perceived rivals. Others involve truly senseless murders."
Holder recounted three of the alleged murders -- one during a botched robbery and two others that resulted from a barroom argument over a spilled drink.
For all the progress made Thursday, Holder said law enforcement's decades-old fight against the mob won't be ending soon.
"Today's arrests mark and important and encouraging step forward in disrupting La Cosa Nostra's operations, but the reality is that our battle against organized crime enterprises is far from over," he said. "This is an ongoing effort. It must be and will remain a top priority for all of us in law enforcement."
Anastasia said that he had never seen an FBI operation so widespread, but said the mob will likely never truly vanish -- perhaps for the better as other ethnic gangs would fight to fill the power void.
"They're all players in the underworld. As the traditional mafia declines, these different groups will fill different vacuums," Anastasia said. "It may be worse that way... because what we may have is disorganized organized crime, which is more violent and more disruptive than organized crime."
ABC News' Dan Harris and Bartley Price contributed to this report.