The following is taken from Fact Sheet - Bureau of Democracy, Human Rights and Labor and Bureau of Public Affairs
Mass graves in Iraq are characterized as unmarked sites containing at least six bodies. Some can be identified by mounds of earth piled above the ground or as deep pits that appear to have been filled. Some older graves are more difficult to identify, having been covered by vegetation and debris over time. Sites have been discovered in all regions of the country and contain members of every major religious and ethnic group in Iraq as well as foreign nationals, including Kuwaitis and Saudis. Over 250 sites have been reported, of which approximately 40 have been confirmed to date. Over one million Iraqis are believed to be missing in Iraq as a result of executions, wars and defections, of whom hundreds of thousands are thought to be in mass graves.
Most of the graves discovered to date correspond to one of five major atrocities perpetrated by the regime.
- The 1983 attack against Kurdish citizens belonging to the Barzani tribe, 8,000 of whom were rounded up by the regime in northern Iraq and executed in deserts at great distances from their homes.
- The 1988 Anfal campaign, during which as many as 182,000 people disappeared. Most of the men were separated from their families and were executed in deserts in the west and southwest of Iraq. The remains of some of their wives and children have also been found in mass graves.
- Chemical attacks against Kurdish villages from 1986 to 1988, including the Halabja attack, when the Iraqi Air Force dropped sarin, VX and tabun chemical agents on the civilian population, killing 5,000 people immediately and causing long-term medical problems, related deaths, and birth defects among the progeny of thousands more.
- The 1991 massacre of Iraqi Shia Muslims after the Shia uprising at the end of the Gulf war, in which tens of thousands of soldiers and civilians in such regions as Basra and Al-Hillah were killed.
- A massacre of Kurds in 1991, which targeted civilians and soldiers who fought for autonomy in northern Iraq after the Gulf war, also resulted in mass graves.
Facts on the Fact Sheet appear to have been those gathered by US Senate committee investigations.
- The remains of 113 Kurds, most of whom were women, children and teenagers, have been uncovered near Samawah.
- Discovery of mass grave sites in Iraq has been done through the analysis of satellite imagery. This has 18 suspected sites, two of which are excavated having 28 and 10 adult males.
- 3,115 corpses uncovered in Mahaweel is one of the largest found (11/2003).
- 2,000 corpses found in Hillah.
- Tony Blair has stated 'We've already discovered, just so far, the remains of 400,000 people in mass graves.' (11/03) The actual number of corpses found is closer to 5,000 (2004). 
The recovery of corpses is reported to be slow due to local violence and the need for identification of corpses, isolation of remains, forensics etc. Relatives have rushed to the graves in remembrance of missing relatives.
- Saddam Hussein killer file
- Knickmeyer, Ellen (2005-04-30). "113 Kurds Are Found In Mass Grave". The Washington Post. http://www.washingtonpost.com/wp-dyn/content/article/2005/04/29/AR2005042901191.html. Retrieved 2010-05-12.
- Burns, John F. (2006-06-05). "Uncovering Iraq's Horrors in Desert Graves". The New York Times. http://www.nytimes.com/2006/06/05/world/middleeast/05grave.html?pagewanted=2&ei=5088&en=f61682fbc3536b01&ex=1307160000&partner=rssnyt&emc=rss. Retrieved 2010-05-12.
- "Expert: 300,000 in Iraq's Mass Graves". Fox News. 2003-11-08. http://www.foxnews.com/story/0,2933,102568,00.html.
- Iraq's Legacy of Terror - Mass Graves
- Beaumont, Peter (2004-07-18). "PM admits graves claim 'untrue'". The Guardian (London). http://politics.guardian.co.uk/iraq/story/0,12956,1263901,00.html. Retrieved 2010-05-12.
- In Saddam's killing fields, BBC News, 14 May, 2003
- Mass Graves of Iraq: Uncovering Atrocities, United States Department of State, December 19, 2003
- Babies found in Iraqi mass grave, BBC News, 13 October, 2004
- Iraq: State of the Evidence - Photographs: Mass Graves and Documentary Evidence of Crimes from Saddam Hussein's Regime, Human Rights Watch
- Iraq's Legacy of Terror: Mass Graves, USAID
- Mass Graves: Iraq
- Pictures of mass graves being exhumed in Iraq