More than half of Iraqis displaced by conflict to other parts of the country have returned to their homes, the UN migration agency said on Thursday.
At the end of December, more than 3.2 million displaced Iraqis had gone home while 2.6 millions still lived away, the International Organization for Migration said.
"The retaking of areas by the Iraqi forces is significant, as is the improvement of security," said IOM communications officer Sandra Black.
More than a third of those internally displaced are in the northern province of Nineveh, after tens of thousands fled second city Mosul during the months-long military campaign to retake the city from ISIS.
More than one million Iraqis have returned home to the Sunni-majority western province of Anbar, from which Iraqi forces expelled the last militants late last year.
Nearly one third are reported to have returned to houses that have been significantly or completely damaged, Agence France Presse quoted Black as saying.
Around 60 percent went back to housing that was only moderately damaged.
Other infrastructure has also been affected in the fighting, with residents in some areas reporting no water or power supply.