What type of information is classified as “Top Secret”?

"Top Secret" classification is reserved for information that, if disclosed without authorization, could cause exceptionally grave damage to national security. This high level of classification is vital because it is used to protect information that is critical to the safety and security of the nation, such as military plans, intelligence sources, and diplomatic negotiations.

The term "exceptionally grave damage" indicates a severe level of potential harm, which distinguishes Top Secret information from lower classifications such as Secret or Confidential. Secret information, for example, might cause serious damage, and Confidential could cause identifiable damage. By defining the gravity of the potential damage, the classification system ensures that only the most sensitive information is protected at the Top Secret level, reflecting its utmost importance to the nation's security.

Publicly available information does not meet the criteria for any classified designation and therefore cannot be classified as Top Secret, further emphasizing the unique nature of the information that falls under this classification.