High Quality Content by WIKIPEDIA articles! The 2003 invasion of Iraq (March 19–May 1, 2003), was the start of the conflict known as the Iraq War, or Operation Iraqi Freedom, in which a combined force of troops from the United States, the United Kingdom, Australia and Poland invaded Iraq and toppled the regime of Saddam Hussein in 21 days of major combat operations. The invasion phase consisted of a conventionally fought war which concluded with the capture of the Iraq capital Baghdad by United States forces.