What is a Vaughn index and when does an agency have to produce one?

A Vaughn index is a document an agency prepares to justify withholding records under the federal Freedom of Information Act (FOIA). Rather than simply asserting that material is exempt, the agency must itemize what it is withholding and explain why each withholding fits a specific FOIA exemption. The name comes from the federal court case that established this requirement.

What a Vaughn index contains

A typical Vaughn index identifies each record or portion being withheld and pairs it with a justification. For each item it generally describes:

• The document or redacted portion (often by date, type, and a general description that does not itself reveal the protected content).
• The specific FOIA exemption claimed (for example, an exemption for classified national security information, privacy, or law enforcement material).
• An explanation of how that exemption applies to that particular record.

The goal is to give the requester and a reviewing court enough detail to evaluate the withholding without disclosing the protected information itself.

When an agency must produce one

A Vaughn index is a creature of litigation, not the initial request stage. When you first submit a FOIA request, the agency generally responds within 20 business days under the federal statute, and it explains any denials in its response letter—but it is not required to hand you a formal Vaughn index at that point.

The obligation typically arises after a requester sues over withheld records. In that lawsuit, a court can order the agency to produce a Vaughn index so the judge can assess whether the claimed exemptions are valid. The agency, which bears the burden of justifying withholdings, must then describe its redactions with enough specificity that the court can rule. The exact form and timing are set by the court handling the case.

A note on state laws

This describes the federal FOIA framework. State public-records laws vary widely, and many use different procedures and terminology for justifying withholdings. Check the specific statute that applies to your request.

For more foundational explanations, see FOIA and public records.