The US-backed army began moving on Hawija two days after capturing the Rashad air base, located 20 miles to the south and used by the militants as a training camp and logistics site.
The recapture leaves just one area of the country still under the control by the depraved militant group, which is a stretch of land along the Syrian border, in western Iraq, including the border town of al-Qaim.
The country’ military said they had killed 196 ISIS militants and recaptured 98 villages.
The offensive on Hawija was carried out by U.S.-backed Iraqi government troops and Iranian-trained and armed Shi’ite paramilitary groups known as Popular Mobilisation.
The operation’s commander, Lieutenant General Abdel Amir Yarallah, said troops, police and paramilitaries had “liberated the whole of the centre of Hawija and are continuing their advance”.
ISIS’s self-declared “caliphate” effectively collapsed in July, when US-backed Iraqi forces captured Mosul, the group’s de facto capital in Iraq, after a gruelling nine-month battle.
The militants’ leader Abu Bakr al-Baghdadi, who declared the caliphate from Mosul in mid-2014, released an audio recording last week that indicated he was alive, after several reports he had been killed.
He called on his followers to keep up the fight despite the setbacks.
Iraq launched an offensive on September 21 to dislodge the terror group from the area north of Baghdad where up to 78,000 people were estimated to be trapped.
The militants continue to control the border town of al-Qaim and the region surrounding it.
They also hold parts of Syrian side of the border, but the area under their control is shrinking as they retreat in the face of two different sets of hostile forces – a US-backed, Kurdish-led coalition and Syrian government troops with foreign Shi’ite militias backed by Iran and Russia.