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Declassification & Classified Records

Classification Levels and Markings Explained

By RM University Editorial Team · Published May 29, 2026

U.S. National-Security Classification Levels Three stacked classification tiers (Top Secret, Secret, Confidential) defined by the level of damage to national security if disclosed, shown separately from Controlled Unclassified Information and Unclassified material. Classified national-security information TOP SECRET Exceptionally grave damage to national security if disclosed SECRET Serious damage to national security if disclosed CONFIDENTIAL Damage to national security if disclosed Increasing sensitivity Controlled Unclassified Information (CUI) Unclassified but protected Not a classification level Unclassified No protection required
U.S. National-Security Classification Levels (CUI is not a classification)

Classification is how the U.S. government protects information whose unauthorized disclosure could damage national security. Under Executive Order 13526, overseen by the Information Security Oversight Office (ISOO), information is assigned one of three levels and marked according to strict rules.

The three levels

  • Confidential — unauthorized disclosure could reasonably be expected to cause damage to national security.
  • Secret — disclosure could be expected to cause serious damage.
  • Top Secret — disclosure could be expected to cause exceptionally grave damage.

Only officials with original classification authority may classify information in the first instance, and only when it falls within defined categories and warrants protection. Over-classification — marking information that doesn’t truly need protection — is a recognized problem the rules actively discourage.

Markings carry the instructions

A classified record’s markings do more than state its level. They identify:

  • The classification level of the document and of individual portions (“portion marking”).
  • The original classification authority and the agency.
  • The reason for classification.
  • Declassification instructions — a date or event when it will be declassified, generally not more than 10 years out (with longer durations allowed for specific, justified categories, up to the 25-year automatic point).

These markings are what later make orderly declassification possible: reviewers rely on them to know what to protect, for how long, and which other agencies hold an interest.

Why markings and recordkeeping go together

Markings are only useful if they survive. Sound recordkeeping preserves the markings and the chain of custody for the decades between classification and review. When markings are lost or records are disorganized, declassification review becomes far slower and riskier. Properly marked, well-managed classified records are the foundation of both safeguarding information today and releasing it appropriately tomorrow.

Sources & further reading

Authoritative government and non-profit references.

How to cite this page

APA

RM University Editorial Team. (2026). Classification Levels and Markings Explained. Records Management University. https://www.recordsmgmt.org/articles/classification-levels-and-markings/

MLA

RM University Editorial Team. "Classification Levels and Markings Explained." Records Management University, 29 May 2026, www.recordsmgmt.org/articles/classification-levels-and-markings/.