But at least one was only unveiled because a court ordered the National Security Agency (NSA) to do so.
The NSA declassified three secret court opinions from the Foreign Intelligence Surveillance Court.
Director of national intelligence James Clapper claimed he released the information "in the interest of increased transparency."
But it wasn't until civil liberties group the Electronic Freedom Foundation (EFF) disclosed a court order that security officials admitted they were forced by a 2012 EFF lawsuit.
In a declassified 2011 court ruling US district judge James Bates rebuked government lawyers for repeatedly misrepresenting NSA surveillance programmes.
He wrote that "the volume and nature of the information it had been collecting is fundamentally different than the court had been led to believe."
He said the court must consider "whether targeting and minimisation procedures comport with the Fourth Amendment" ban on unreasonable search and seizure.
"This court is troubled that the revelations regarding NSA acquisition of internet transactions mark the third instance in less than three years in which the government has disclosed a substantial misrepresentation regarding the scope of a major collection programme," he added in a heavily censored footnote.
Judge Bates said the NSA was gathering internet data years before it was authorised by the Patriot Act in 2008.