The entire China email from aide Huma Abedin was redacted and on Sudan, a page and a half about "calls" Clinton said she was willing to make was likewise blacked out.
They were part of a massive release of 7,000 pages of emails from the former secretary of state's personal email server - her largest email release to date.
"We're producing more documents this month than we have produced in the previous three releases," department spokesman Mark Toner said earlier Monday.
But the sheer number of emails that have been redacted stands as the latest example of how much sensitive material was contained in Clinton's email transactions.
The Clinton campaign insists that Clinton herself never sent or received messages marked classified at the time.
Toner, in a briefing with reporters, likewise said none of the emails being released Monday was considered classified at the time.
Rather, he said, "somewhere around 150" have been "subsequently upgraded" to classified.
The department, though, has clashed on this point with the intelligence community inspector general, which previously has determined certain emails contained classified information from the start and should have been handled as such.
Fox News first reported that two emails that triggered the FBI investigation also included classified material. Among them was an email from Clinton aide Huma Abedin which, Fox News has learned, contained classified intelligence from three agencies.
Toner said Monday that the latest release means the department will have produced more than 25 percent of the full set of Clinton emails, exceeding a court-ordered target.
This comes after the department last month fell short of the court-ordered goal. In that release, emails showed the government censored passages to protect national security at least 64 times in 37 messages, including instances when the same information was blacked-out multiple times.
Department officials say all the censored information in the latest group of emails is classified at the "confidential" level, not at the higher "top secret" or compartmentalized, the officials said.
At Monday's briefing, Toner also would not say whether Clinton broke internal department rules for handling correspondence with foreign governments.