P.O. Box 1142 was one of the most secret U.S. intelligence facilities of World War II—an interrogation and espionage center hidden inside Fort Hunt, Virginia. It operated under total secrecy, left almost no paperwork (most was burned in 1945), and wasn’t publicly acknowledged until the 2000s. The details below come directly from the historical sources returned in your search .

 P.O. Box 1142 — Complete Breakdown

 What It Was

• A top‑secret U.S. military intelligence facility at Fort Hunt, Virginia, active during WWII.
• Operated under the Military Intelligence Service (MIS).
• Its name—P.O. Box 1142—was literally a mailing address used as a cover identity.

 Two Intelligence Wings

P.O. Box 1142 housed two major programs:

1. MIS‑Y — Interrogation of German POWs

• Main mission: interrogate high‑value German prisoners.
• Interrogators were often Jewish refugees from Germany who spoke native German and understood the culture.
• Notable prisoners included:
  • Wernher von Braun (rocket scientist)
  • Reinhard Gehlen (German intelligence chief who later worked with the CIA)
  • Heinz Schlicke (infrared detection expert)

2. MIS‑X — Escape & Evasion Support

• Mission: help American POWs escape German camps.
• Created coded messages, escape tools, and smuggled items inside “care packages.”

 Location & Cover

• Located at Fort Hunt Park, near Washington, D.C.
• The site had previously been used for ROTC training and CCC camps before being converted for intelligence work.
• Personnel were told never to reveal the location or their work, even to family.

 Secrecy & Destruction of Records

• Six days after Japan’s surrender (August 1945), staff were ordered to burn all documents related to the program.
• Food supplies were donated, buildings dismantled, and the site returned to the National Park Service.
• Veterans were sworn to secrecy for decades; many didn’t speak until the 2000s.

 What Happened There

Interrogation

• Prisoners were questioned about:
  • V‑2 rockets
  • U‑boat technology
  • Radar and infrared systems
  • German intelligence networks
• Interrogations were psychological, not physical—no torture was used.

Scientific Debriefing

• After the war, German scientists brought to the U.S. (including via Operation Paperclip) were debriefed at the site.

Intelligence Innovations

• Development of:
  • Covert communication methods
  • Escape kits
  • Concealed tools (e.g., compasses in buttons, maps in playing cards)

 Why It Mattered

P.O. Box 1142 contributed to:

• The U.S. understanding of German rocket and weapons programs
• Early Cold War intelligence (via Gehlen and others)
• The foundation of post‑war U.S. intelligence operations
• The success of American POW escapes in Europe

Its work fed directly into:

• Operation Paperclip
• CIA early intelligence structures
• U.S. missile and aerospace programs

 Modern Recognition

• The U.S. government officially acknowledged P.O. Box 1142 only in 2007.
• The National Park Service now maintains a memorial at Fort Hunt Park.
• Oral histories from surviving veterans are archived by the NPS.

 Sources

• Wikipedia summary of P.O. Box 1142
• Wikiwand overview 
• National Park Service oral history project 
• Historic Times deep‑dive on the facility’s secrecy and declassification
• NPS article on POWs and intelligence at Fort Hunt

Here’s a clear, historically grounded timeline of P.O. Box 1142, built directly from the sources returned in your search results. It tracks the facility from its creation in 1942 through its rediscovery and public acknowledgment in 2007. All factual points are cited from the retrieved pages, including Wikiwand , Historic Times, SpotterUp , and the National Park Service PDF.

 Timeline of P.O. Box 1142 (1942–2007)

 1942 — Establishment

• The U.S. Military Intelligence Service establishes a secret intelligence center at Fort Hunt, Virginia, known only by its mailing address: P.O. Box 1142 .
• Two major intelligence wings are based there:
  • MIS‑Y — interrogation of high‑value German POWs 
  • MIS‑X — escape‑and‑evasion support for Allied POWs in Europe 

 1942–1945 — Full Operational Period

Interrogation & Intelligence Work

• MIS‑Y interrogates Germany’s most valuable military prisoners, including:
  • Wernher von Braun (V‑2 rocket program) 
  • Reinhard Gehlen (German military intelligence) 
  • Heinz Schlicke (infrared detection technology) 
• Many interrogators are Jewish refugees from Germany, chosen for their native fluency and cultural knowledge.

Escape & Evasion Operations

• MIS‑X designs covert tools, maps, and coded messages to help Allied POWs escape German camps.

Document Analysis

• The facility also hosts MIRS, a captured‑document analysis unit.

 August 14, 1945 — Japan Surrenders

• Six days later, staff receive the order: “Burn all documents.”
  They destroy nearly all records of the facility’s existence .

 Late 1945–1946 — Shutdown

• Buildings are dismantled, food supplies donated, and Fort Hunt is returned to the National Park Service.
• Personnel are sworn to secrecy and do not speak of their work for decades.

 1946–2006 — Total Silence

• For 60 years, the U.S. government does not acknowledge P.O. Box 1142.
• Veterans keep their oath and rarely discuss their service.

 2007 — Public Acknowledgment

• Surviving veterans (now in their 80s and 90s) finally speak publicly when the U.S. government officially acknowledges the facility.
• The National Park Service begins recording oral histories and preserving the site.

 Condensed Timeline Table

Year	Event
1942	P.O. Box 1142 established at Fort Hunt, VA
1942–45	MIS‑Y interrogations; MIS‑X escape operations; MIRS document analysis
Aug 1945	Order to burn all documents after Japan’s surrender
1946	Facility dismantled; secrecy oath continues
1946–2006	No public acknowledgment; veterans remain silent
2007	U.S. government officially recognizes P.O. Box 1142; veterans interviewed

 Sources

Wikiwand summary of P.O. Box 1142
Historic Times deep‑dive on the facility’s secrecy and destruction of records
SpotterUp historical overview
Everything Explained (notable prisoners and interrogators)
National Park Service PDF on the programs at Fort Hunt