-March 17: President Bush gives Saddam Hussein 48-hour deadline to give up power.
-March 20: The U.S.-led invasion is launched.
-May 1: On an aircraft carrier under a "Mission Accomplished" banner, Bush declares "major combat operations in Iraq have ended."
-July 13: Governing Council of U.S.-selected Iraqi officials takes office.
-Dec. 13: Saddam captured in underground hideout near Tikrit.
2004: RISE OF INSURGENCY.
-April: Photographs surface of prisoner abuse at Abu Ghraib prison.
-March 31: Four private security employees ambushed and killed in Fallujah, and their bodies hung on a bridge. U.S. forces later attack the city in some of the first major urban battles against Sunni insurgents.
-June 28: U.S.-led occupation authority turns over formal power to interim government.
-September: U.S. military deaths reach 1,000.
-Oct. 6: Top U.S. arms inspector in Iraq finds no evidence that Saddam's regime produced weapons of mass destruction after 1991, discounting a main justification of the war.
-November: Deadliest month to date for U.S. forces: 137 deaths.
-Jan. 30: Iraqis elect 275-seat National Assembly in the country's first national elections since Saddam's fall. Shiite Muslim-dominated coalition wins 48 percent, Kurdish alliance 26 percent. Most Sunni Arabs boycott voting.
-April 6: National Assembly elects Kurdish leader Jalal Talabani as president.
-Aug. 31: At least 1,000 Shiite pilgrims killed in a bridge stampede caused by rumors of a suicide bomber in Baghdad.
-Oct. 15: Iraqi voters approve constitution in referendum, with strong Shiite and Kurdish support. Sunni Arabs largely opposed and win a promise that the next parliament will consider amendments.
-October: U.S. military deaths reach 2,000.
-Dec. 15: Iraqis elect new parliament with Shiite parties winning biggest bloc.
2006: VIOLENCE SPREADS.
-Feb. 22: In Samarra, suspected Sunni insurgents detonate two bombs inside the revered Shiite Askariya shrine, blowing the top off its landmark golden dome. The attack sharply escalates sectarian bloodshed and increases fears of a civil war.
-June 8: American airstrike outside Baqouba kills al-Qaida-linked insurgent leader Abu Musab al-Zarqawi and his spiritual adviser, Sheik Abdul-Rahman. "A significant victory in the war on terror," says Bush.
-Nov. 5: Saddam sentenced to death by Iraqi court.
-Dec. 6: The Iraq Study Group calls for a change in U.S.
policies in Iraq, saying conditions are "grave and deteriorating" and recommends gradual transition of combat role to Iraqi forces.
-Dec. 30: Saddam is hanged.
-Dec. 31: U.S. troop deaths reach 3,000.
2007: TROOP BUILDUP.
-Jan. 10: Bush announces that more than 20,000 additional U.S.
troops will be sent to Baghdad and Anbar province in a mission dubbed "the surge."
-Jan. 16: United Nations reports that 34,452 Iraqi civilians were slain in 2006, nearly three times more than the government reported.
-June 24: Saddam's cousin, known as "Chemical Ali," and two other former regime officials are sentenced to hang for atrocities against Kurds in the 1980s.
-July 12: White House report required by Congress says Iraq has made satisfactory progress on eight of 18 political and security "benchmarks," unsatisfactory progress on eight others and that it is too early to judge progress on two.
-Aug. 14: Four suicide bombers hit a Kurdish Yazidi community in northwest Iraq, killing at least 520 people and wounding 350 others.
-Sept. 10: Gen. David Petraeus tells Congress he envisions the withdrawal of roughly 30,000 troops from Iraq by mid-2008.
-Oct. 23: U.N. refugee agency says nearly 2.3 million people are displaced inside Iraq, and more than 2.2 million have fled to neighboring countries.
-Jan. 9: The World Health Organization and the Iraqi government estimates that about 151,000 Iraqis died from violence in three years after the U.S. invasion.
-Jan. 25: Iraqi Prime Minister Nouri al-Maliki announces plans for "decisive" offensive against al-Qaida in Iraq in northern city of Mosul after two days of bombings kill nearly 40 people.
-Feb. 1: Two woman carrying explosives enter pet markets in Baghdad, killing nearly 100 people in the blasts.
-Feb. 25: The Pentagon says 140,000 U.S. troop levels in Iraq will be about 140,000 - higher than the 132,000 before the surge.