A non-combatant evacuation operation (NEO) is an operation conducted to evacuate civilians from another country, generally due to a deteriorating security situation.
According to United States Military Joint Publication 3-68, Noncombatant Evacuation Operations:
This means that at times American citizens may become endangered in locations outside of the United States. This is usually due to civil unrest or war. However, it may also be due to a natural disaster. The U.S. Ambassador has the responsibility, according to law, to request a NEO. Once he does, the government will determine whether or not the evacuation should be done with civilian resources, such as the Civil Reserve Air Fleet (CRAF), or with military forces. Even if military forces conduct the evacuation, the Ambassador remains in charge of the evacuation.
The method of evacuation could include sealift, airlift, or even by road.