According to this executive order:

Records exempted from automatic declassification under this paragraph shall be automatically declassified on December 31 of a year that is no more than 75 years from the date of origin unless an agency head, within 5 years of that date, proposes to exempt specific information from declassification at 75 years and the proposal is formally approved by the Panel.

So, there are cases when the information might not be declassified even after 75 years (if I understand correctly - the paragraph is not clear for me).

However, according to this archive article:

The Order also recognizes that some information might remain sensitive and pose a threat to the national security if released at the 25-year mark such as information which reveals the identity of a confidential human source, human intelligence source, or key design concepts of weapons of mass destruction, which may have a duration up to 75 years.

Q1: Is 75 years a maximum threshold for information declassification or it can be delayed indefinitely?

Q2: How was this 75 year limit chosen? For me it seems about the life expectancy in developed countries.

  • 3
    So what you're saying is.. we'll get the juicy stuff from WWII in about 3 years... Aug 31, 2017 at 21:22
  • @easymoden00b Most of it, at least.
    – JAB
    Sep 1, 2017 at 18:52

1 Answer 1


Your reading of that executive order is correct. Information that may (for example) reveal details of the design of nuclear weapons can be kept secret indefinitely. However this is intended to be exceptional, and requires a special procedure.

The timing was clearly chosen for convenient multiples of 25 years. One can be reasonably confident that any person actively engaged in espionage 75 years ago will now be dead, and so material that may reveal the identity of foreign agents can be released without putting them at risk. The UK has a similar 100 year rule, again to ensure that any people mentioned are very likely to be dead by the time the material is released.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .