Manhattan Project Historical Marquee behind Fence Opt

Behind-the-Fence Tours

Manhattan Project National Historical Park Tours at LANL

The most current information about the tours will always appear on this webpage. Please check back or bookmark this page for any updates.

These unique, guided tours take participants “behind the fence” into secure areas not generally accessible to the public. Tours on Lab property are limited due to the secure nature of Los Alamos National Laboratory, but a series of tours are offered twice a year with advanced registration. On these tours you will see the Pond Cabin, which served as an office for Emilio Segrè’s Radioactivity Group studying plutonium; a battleship bunker used to protect equipment and staff during implosion design explosives testing; and the Slotin Building, site of Louis Slotin’s criticality accident.

Each tour lasts approximately four hours and there are two tours per day with a maximum of 30 participants on each. Please see the upcoming tour dates below along with requirements for participation.

  • May 13, 2025
  • May 14, 2025
  • May 15, 2025
  • Oct 14, 2025
  • Oct 15, 2025
  • Oct 16, 2025

Participants for the May tours will be selected via a random lottery. Registration for the lottery will open on February 19 and close on February 26. All lottery entrants will receive an email informing them of the results in early March. A separate lottery will be conducted later in the year for the October tours. Lottery registration is online only. 

Click here to enter the lottery between February 19 and February 26.

Safety and security are vital at Los Alamos National Laboratory. Individuals selected in the lottery will need to verify their eligibility to visit a national security site before confirming their tour registration.

Requirements

Tour participants:

  • Must be U.S. citizens with original documentation, including an original birth certificate, passport, tribal identification, or other qualified document;
  • Must be at least 18 years of age;
  • Must be able to walk short distances, stand for 30 minutes, climb stairs, and traverse over uneven surfaces;
  • Must wear sturdy footwear and long pants;
  • Are not allowed to bring cell phones, cameras, Bluetooth devices, or recording devices of any kind onto the site;
  • Must follow all other requirements listed in the registration process.

To learn more about Manhattan Project history in the Los Alamos area, see our Plan your visit page.