Earlier Sunday, the Kurdish region's president Masoud Barzani pledged the vote would be held despite pressure from Baghdad and the global community.
In Kirkuk, authorities declared a curfew an hour and a half before polls closed as jubilant Kurds started to celebrate.
Kurds showed off their ink-stained fingers as they left polling stations on September 25, showing they had voted. They want jobs, opportunity and freedom before anything else.
Baghdad on Sunday urged the world countries not to purchase oil from Kurdistan Region in response to the referendum hours after Prime Minister Haider al-Abadi vowed to take "necessary measures" to protect the unity of Iraq.
Iraq's semi-autonomous Kurdistan Region kicked off an independence referendum on Monday in the face of strong objections from the central government in Baghdad and urgent calls from the worldwide community to scrap the vote.
The vote went ahead despite objections from officials in Baghdad.
United Nations, Sep 25 UN Secretary-General Antonio Guterres today expressed concern about the potentially destabilizing effects of a referendum held by Kurds on independence from Iraq.
The State Department said last week the referendum would preclude the possibility of negotiations with the Baghdad central government, and present a high cost for "all Iraqis, including Kurds".
"The Kurdish leadership now has the mandate to negotiate with Baghdad on an amicable separation, on a new relationship between Erbil and Baghdad", she told Al Jazeera from Washington, DC. Iran has a Kurdish population, but they have not experienced the same level of violence as Kurds in Turkey and Syria have in recent years.
Earlier Monday, Turkish President Recep Tayyip Erdogan said Turkey would take political, economic, commercial and security steps against the Kurdish Regional Government.
"We stress again that we will take all measures arising from worldwide law and the Turkish parliament's authority in the face of every kind of threat to our national security in Iraq generally", it said.