Which classification level is the highest in the DoD?

The highest classification level in the Department of Defense (DoD) is Top Secret. This classification is used to protect information that, if disclosed, could cause exceptionally grave damage to national security. The Top Secret classification covers a wide range of sensitive materials, including military plans, intelligence operations, and national defense strategies, which require stringent controls and limited access to authorized personnel only.

In contrast, the other classification levels serve different purposes and indicate varying degrees of sensitivity. Secret information is classified as such because unauthorized disclosure could cause serious damage to national security, but it is not as sensitive as Top Secret information. Confidential information is protected because unauthorized disclosure could cause damage to national security, but it is considered less sensitive than both Secret and Top Secret. The term "Restricted" is not an official classification level as defined by the DoD and is typically associated with internal handling controls rather than classification of information. This context illustrates why Top Secret stands out as the highest classification level.