U.S. Army Major Nidal Hasan murders 13 and wounds 32 at Fort Hood, Texas in the deadliest mass shooting at a U.S. military installation.

Nidal Malik Hasan is an American former United States Army major, physician, and mass murderer convicted of killing 13 people and injuring 32 others in the Fort Hood mass shooting on November 5, 2009. Hasan, an Army Medical Corps psychiatrist, admitted to the shootings at his court-martial in August 2013.

Fort Hood is a United States Army post located near Killeen, Texas. The post is located halfway between Austin and Waco, about 60 mi (100 km) from each, within the U.S. state of Texas. The post is the headquarters of III Armored Corps and First Army Division West and is home to the 1st Cavalry Division and 3rd Cavalry Regiment, among others.

Texas is the most populous state in the South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the west, and an international border with the Mexican states of Chihuahua, Coahuila, Nuevo León, and Tamaulipas to the south and southwest. Texas has a coastline on the Gulf of Mexico to the southeast. Covering 268,596 square miles (695,660 km²) and with over 31 million residents as of 2024, it is the second-largest state by area and population. Texas is nicknamed the Lone Star State for its former status as an independent country, the Republic of Texas.

On November 5, 2009, a mass shooting took place at Fort Hood near Killeen, Texas, United States. Nidal Hasan, a U.S. Army major and psychiatrist, fatally shot 13 people and injured more than 30 others. It was the deadliest mass shooting on an American military base and the deadliest terrorist attack in the United States since the September 11 attacks until it was surpassed by the San Bernardino attack in 2015.