The department says portions of 64 of the documents were upgraded to the "confidential" level, although none of the information was marked "classified" at the time the emails were sent.
None of the 562 documents released yesterday was upgraded to "secret" or "top secret." The 1,116 pages made public yesterday bring the total page count of released Clinton emails to 46,946.
The State Department plans to finish making her emails public on February 29, a day before the critical Super Tuesday primaries. Clinton has struggled to put the email controversy to rest as she seeks the Democratic presidential nomination.