The turnover of security to Iraqi authorities, however, doesn't mean the withdrawal of U.S. troops, which number about 25,000 in the desert region that extends from the western outskirts of Baghdad to the borders of Syria, Jordan and Saudi Arabia, according to the Associated Press.
But U.S. troops will reduce their patrols and focus on training Iraq's army and police.
"Iraqi forces will now take the lead in security operations in Anbar, with American troops moving into an overwatch role," said President Bush in a statement.
Anbar is the 11th of Iraq's 18 provinces to switch to Iraqi control. The area was the center of the Sunni insurgency, and American officials warned that the struggle against al-Qaida in Iraq and other insurgents was not over in the region.
"This war is not quite over, but it's being won and primarily by the people in Anbar," said Marine Maj. Gen. John Kelly, the top U.S. commander in Anbar, during the handover ceremony, reported the AP. "Al-Qaida has not been entirely defeated in Anbar, but their end is near and they know it."
Al-Qaida in Iraq and its leader, Abu Musab al-Zarqawi, used Anbar as a base for staging ground attacks in Baghdad until he was killed in a U.S. strike in 2006.
Many Iraqi tribal leaders, including those in the region's Sunni Arab community, opposed al-Qaida's tactics, such as the mass killing of Shiite civilians and Sunni leaders who refused to accept al-Qaida's rule.
The Sunni sheiks created so-called awakening councils that joined forces with U.S. troops to drive al-Qaida from the province.
Since then, Anbar is considered one of the quieter regions of Iraq, but there is still lingering tensions between the awakening councils and predominately Shiite government in Baghdad.
According to Kelly, the central government in Baghdad can help maintain the calm in Anbar.
"What Anbar needs now, what will end this conflict forever and prevent al-Qaida from ever coming back, is economic development, reconstruction and funds for compensation," he said, according to the Los Angeles Times.