Haider al-Abadi visited the newly-liberated town of Qaim and the nearby Husaybah border crossing in far western Iraq on Sunday, Al-Iraqiya TV said.
He then raised the Arab country’s flag at a border crossing with Syria, it added.
Both districts sit along what was once an important supply route used by Daesh when the group controlled large areas in Syria and Iraq.
Iraqi forces drove Daesh from Qaim and surrounding areas last week, in what experts said marked the end of the conventional war against the terror group in Iraq, AP reported.
The Takfiri militants are expected to rely more on insurgent-style attacks now that they no longer hold significant territory.