The investigation into Hillary Clinton's emails has been formally closed without any criminal charges, US Attorney General Loretta Lynch said.
The decision had been expected and was largely a formality given FBI Director James Comey's recommendation a day earlier against any prosecution.
Ms Lynch had previously said she intended to accept the recommendations of the FBI director and of her career prosecutors.
It officially closes an FBI investigation that had dogged Mrs Clinton for the last year and proved a major distraction on the campaign trail as she emerged as the Democratic presidential frontrunner.
Ms Lynch said she met Mr Comey and prosecutors on Wednesday and agreed that the investigation, which looked into the potential mishandling of classified information, should be concluded.
"I received and accepted their unanimous recommendation that the thorough, year-long investigation be closed and that no charges be brought against any individuals within the scope of the investigation," she said.
Mr Comey, in an unusually detailed and public accounting of the investigation on Tuesday, said "no reasonable prosecutor" would pursue a criminal case and said he was advising the justice department against bringing any charges.
But he also rebuked Mrs Clinton, who relied exclusively on a private email server as secretary of state, and her aides for being "extremely careless" with their handling of classified information.
"There is evidence to support a conclusion that any reasonable person in Secretary Clinton's position ... should have known that an unclassified system was no place" for sensitive conversations, Mr Comey said.
Mrs Clinton's likely election opponent, Donald Trump, responded during a rally in Cincinnati, contrasting her statements about the email server with what Mr Comey said and labelling the former secretary of state "a dirty, rotten liar".
Reading from a script, which he rarely does, Mr Trump outlined several of what he called Mrs Clinton's "lies" about the servers, including that she only used one email device and that she did not have any emails marked as "classified" on the private server.
"She made so many false statements," Mr Trump said. "Is she going to be brought before Congress? Is something going to happen?"
Mr Comey was scheduled to face questions about the decision in an appearance on Thursday before the House Oversight and Government Reform Committee. Ms Lynch is scheduled for an oversight hearing next week on Capitol Hill.
FBI agents spent the last year investigating the matter following a referral from the intelligence community's inspector general.
As part of the investigation, investigators pored through tens of thousands of State Department emails and interviewed top Clinton aides - and finally, Mrs Clinton herself this past weekend.
Despite his critical assessment of Mrs Clinton's email practices, Mr Comey said there was no evidence that anyone intentionally or wilfully mishandled classified information.
"No charges are appropriate in this case," he said.
