Answer:
The Marine barracks that was destroyed by a terrorist bomb during the Reagan administration was located in Lebanon.
Step-by-step explanation:
The attack against the barracks in Beirut was a terrorist attack that took place in October 1983 (during the Lebanese civil war), and in which 241 US Marines, 58 French paratroopers, and six Lebanese civilians were killed.
A car bomb loaded with explosives of a power equivalent to 5000 kg. of TNT, impacted and detonated against the US Marines barracks, completely destroying the structure. A few minutes later a similar event occurred at the French command post.
The Islamic Jihad organization assumed responsibility for the attack, although it is believed that the real responsible was Hezbollah, the terrorist organization financed by Iran.