LANL, National Park announce lottery for behind-the-fence Manhattan Project tours May 5–7

The Manhattan Project National Historical Park and Los Alamos National Laboratory announced guided "behind‑the‑fence" tours at LANL will run May 5, 6 and 7, the park news release says, with reservation slots to be distributed through an online lottery. Reservations will be allocated via an online lottery system. Lottery registration opens on February 23 and closes on March 4. Tour guests will be selected and notified by the end of March.

Organized by Los Alamos National Laboratory in collaboration with the National Nuclear Security Administration’s Los Alamos Field Office and the National Park Service, the tours are described as limited, half‑day experiences. The LANL bulletin previously called them "exclusive, four-hour tours" that take participants "behind the fence" at Laboratory property and give access to buildings normally closed to the public.

The itinerary highlights three core Manhattan Project sites at Los Alamos. Visitors will "step inside the original Pond Cabin, where physicist Emilio Segrè’s team made the pivotal discovery that the Thin Man plutonium bomb design would not work," the materials say. Guests also will "descend into a bunker where experiments helped determine whether the Trinity nuclear test would succeed" and "see the Slotin Building, where a fatal criticality accident transformed the safety culture of Los Alamos National Laboratory."

Access rules for the May 5–7 series are strict. The park release notes participants must be at least 18 years old, U.S. citizens and able to provide proof of citizenship at tour check‑in, and the tours are not open to current LANL employees. The National Park Service emphasizes that "nearly all the park’s historic properties at Los Alamos are located 'behind the fence' on a secure federal Department of Energy reservation" and that "these tours are only offered three times a year. Reservations are required."

Allocation methods have varied by year. LANL’s 2024 announcement for June 11–13, 2024 used first‑come, first‑served registration beginning May 1 at 11 a.m. MDT with only 180 openings available. VisitLosAlamos listed an October 14–16, 2025 lottery that accepted entries through June 28 with selections made July 1, 2025. Some third‑party packaged trips have charged a transportation fee, event listings show a $45 pickup offering from La Fonda On the Plaza for a May 10, 2024 shuttle that was marked SOLD OUT, suggesting practical travel costs may apply even when official tour registration is free.

The Slotin Building’s history, described in the release as a site that "transformed the safety culture of Los Alamos National Laboratory," underscores occupational and public health dimensions of the tours. Bringing those buildings into public view amid strict national security access rules can prompt community conversations about worker safety, environmental legacy, and who in Los Alamos gets to see this history, given the citizenship requirement and transportation costs noted in event listings.

For questions or to confirm registration details for the May 5–7 tours, LANL's contact listed in tour notices is Tricia Ware at (505) 695‑3026 or tware@lanl.gov. Selected applicants will be notified by the end of March, and the coordinated tours will remain among the few annual opportunities to visit Los Alamos properties tied directly to the Manhattan Project.