Automatic Declassification at 25 Years

The default rule for most historically valuable classified records is simple in principle: when they reach 25 years of age, they are automatically declassified — unless a specific, narrow exemption applies. This is the engine that steadily opens the historical record to the public.

How the rule works

Under Executive Order 13526, classified records that have permanent historical value are subject to automatic declassification at 25 years. The principle is that classification should be temporary, and after a quarter-century most national security information no longer needs protection. So rather than requiring a request or relying solely on agency initiative, eligible records are declassified automatically when they hit the mark.

The exemptions

Not everything is released at 25 years. Agencies may exempt specific information that still requires protection — for example, information that would reveal intelligence sources and methods, identify confidential human sources, or concern weapons of mass destruction. These exemptions must be justified, and there are mechanisms — including the Interagency Security Classification Appeals Panel (ISCAP) — to check them. Some categories can be protected beyond 25 years, but the default is release.

The review burden

Automatic declassification creates an enormous, recurring workload. Each year a new wave of records crosses the 25-year threshold and must be reviewed before the deadline to:

• identify any genuinely exempt information,
• account for other agencies’ equities (information one agency can’t release without another’s concurrence), and
• redact what must stay protected while releasing the rest.

The National Declassification Center (NDC) at the National Archives coordinates much of this work for permanently valuable records, and agencies run systematic review programs to stay ahead of the clock.

Why recordkeeping is the foundation

The 25-year rule only works if records are well managed across the decades in between — accurately marked, properly stored, and findable when their review date arrives. Lost or disorganized classified records cannot be reviewed and released on time. Automatic declassification sits alongside mandatory declassification review and systematic review as the three pathways for releasing classified information. See the declassification hub for more.