The following are events related to the Global War On Terrorism (GWOT) that took place on this day.

2003

• U.S. and British forces invade Iraq. U.S. Special Forces move into western and northern Iraq.
• Marines from I MEF crossed the Kuwait border into southern Iraq in the first push to Baghdad. A firefight between American and Iraqi ground forces occurred when a patrol of light armored vehicles from the 1st Marine Division encountered two Iraqi armored personnel carriers. The Marines destroyed the enemy and moved forward quickly, capturing key facilities in Rumeila, Iraq’s southern oil fields. Marines saved all but nine of nearly 500 oil wells from sabotage before continuing toward the Iraqi capital.
• With the lapse of the 48-hour deadline, Operation Iraqi Freedom began with the launching of approximately 40 Tomahawk cruise missiles at 5:34 a.m. The missiles, which were launched from six U.S. Navy ships, were aimed at three designated military targets around Baghdad, Iraq, in an attempt to kill or maim Hussein. U.S. Air Force F117 stealth fighters were also involved in the opening strike.

2004

• Marine Major General James N. Mattis, commander of the Camp Pendleton-based 1st Marine Division, formally assumed responsibility of the Al Anbar and Northern Babil provinces from the Army’s 82nd Airborne Division. The relief-in-place ceremony bequeathed to the Marine Corps the majority of the volatile Sunni Triangle region north and west of Baghdad, an area where American forces had been under nearly daily attacks from insurgents. Nearly two-thirds of the 1st Marine Division Marines were also part of the original invading forces a year ago but had a new mission the second time around. The new mission was to help the fledgling Iraqi security forces and build upon the humanitarian efforts of the departing Army unit.

2005

• Vice Chairman of the Joint Chiefs of Staff, Marine Gen Peter Pace, traveled to Camp Lemonier to personally thank service members serving with the Combined Joint Task Force-Horn of Africa (CJTF-HOA) in Djibouti. The task force was deployed to the African region to help prevent the spread of terrorism.

2007

• Start of Operation Arrowhead Strike 9 in Iraq

Casualties on March 20:

• SANDRI, MATTHEW JOSEPH – March 20, 2004
• TAYLOR, MARK DOUGLAS – March 20, 2004
• VEGA, MICHAEL WILLARD – March 20, 2004
• VICENTE, DAVID MARQUES – March 20, 2004
• MARTINEZ, FRANCISCO GREGORIO – March 20, 2005
• THOMASON, PAUL WILLIAM III – March 20, 2005
• CORNELL, WAYNE RICHARD – March 20, 2007
• GLAWSON, CURTIS ERIC JR – March 20, 2007
• RICHARDSON, STEPHEN KARL I – March 20, 2007
• GEARY, DANIEL JOSEPH – March 20, 2009
• ESCOBEDO, JOSE REFUGIO JR – March 20, 2009
• MALACHOWSKI, JAMES MICHAEL – March 20, 2011