They were among several hundred hostages rescued
by the military from the Sambisa Forest, a stronghold of the Islamist militant group, in the past month.
Since their rescue, the women and children had been staying at a displaced persons camp in Yola, capital of Nigeria's northeastern Adamawa state.
But officials with Nigeria's National Emergency Management Agency and the Nigerian military said the move to a new location was necessary to enable them to pursue a rehabilitation program and re-enter society.
The transfer took the rescued hostages and their relatives by surprise, according to one witness.
The women and children were ferried in trucks on Tuesday afternoon to the airport, from where they were airlifted to an unknown destination, said Sambo Halliru, a relation of one of the rescued women who was at the camp at the time of the evacuation.
"We don't know where they took them to. The women didn't seem to know where they were being taken to because the soldiers didn't make any explanation to the women," Halliru said.
Mohammed Kanar, the coordinator for Nigeria's National Emergency Management Agency in the northeast, said 260 women and children had been moved to a location "where they can undergo psychotherapy without distraction."
Another 15 are still in hospital receiving treatment for injuries sustained during the rescue operation and illness they developed during their long trek to safety, he said.
"The Malkohi camp in its present state is not conducive for that due to uncontrolled visits by relations and members of the public which deprive the rescued women the needed concentration to overcome their trauma induced by their captivity in the hands of Boko Haram," Kanar said, declining to say where the women were moved to for security reasons.
A statement from Nigeria's military put the number of women and children moved from the camp at 275, but gave a similar reason for the transfer.
The former hostages will now be able to undergo a psychosocial rehabilitation program arranged by the Office of the National Security Adviser in a safe, more conducive location, it said.
The rehabilitation program is part of an initiative by the National Security Adviser, Sambo Dasuki, aimed at countering terrorism.
Boko Haram has said its aim is to impose a stricter enforcement of Sharia law across Nigeria, which is split between a majority Muslim north and a mostly Christian south.
More than 2,000 women and girls have been abducted by Boko Haram since last year, according to Amnesty International.