What Does a Section 229 Boundary Mean for the SLAC National Accelerator Laboratory?

The Legal Mechanism Behind the Boundary

Section 229 of the Atomic Energy Act of 1954 authorizes the Department of Energy to prohibit unauthorized entry and the unauthorized introduction of weapons or dangerous materials onto described facilities and property. The implementing regulation sits at 10 CFR part 860, titled Trespassing on Department of Energy Property. The notice published on November 4, 2026, invokes both the statute and the regulation. It does not create new rules; it applies existing ones to a specific geographic area.

The document was signed on October 5, 2026, by Tyler M. Walker, Real Estate Contracting Officer, acting under delegated authority from the Secretary of Energy. Jennifer Hartzell, Alternate Federal Register Liaison Officer, submitted it for publication on November 2, 2026. The effective date matches the publication date. No comment period preceded this action. The notice is effective immediately upon publication.

This designation carries federal weight.

Where the Line Is Drawn

The laboratory occupies approximately 426.3 acres. Its physical address is 2575 Sand Hill Road, Menlo Park, CA 94025. The site sits in the City of Menlo Park, San Mateo County, California. The boundary is marked by a combination of signage at entrances and along the perimeter, chain link fencing, and other physical features which surround the facility. The notice does not provide coordinates or a metes-and-bounds description. It references the physical markers as the operative boundary indicators.

Signs and fences define the edge.

Who Controls the Land

The United States Department of Energy does not own the land in fee simple. Control comes through a long-term ground lease between the Department of Energy and the Board of Trustees of the Leland Stanford Junior University. Stanford University operates the laboratory under a separate management and operating contract. The lease arrangement means the Section 229 designation applies to property the federal government controls but does not hold title to. The notice makes no mention of any change to the lease terms or the Stanford management contract.

Federal control rests on a lease.

What the Designation Actually Prohibits

Two categories of conduct become federal violations within the marked boundary. Unauthorized entry is prohibited. Unauthorized introduction of weapons or dangerous materials is prohibited. The notice does not define "weapons" or "dangerous materials" beyond the regulatory text at 10 CFR part 860. It does not list specific penalties. The regulation itself provides for fines and imprisonment. The notice does not address whether existing public roads crossing the site remain open. It does not describe an authorization process for visitors or contractors. The contact for further information is Tyler M. Walker at 301 Laboratory Road, Oak Ridge, TN 37830, email tyler.walker@doe.gov, telephone (865) 469-1183.

Entry and weapons are banned.