Code of Federal Regulations Title 43. Public Lands:  Interior § 43.20.511 Carrying of firearms

Employees, except those specifically designated to perform enforcement, police or other official duties requiring the use of firearms, are prohibited from carrying or having in their possession firearms on property under the control of the Secretary. Employees who are officially stationed in parks, refuges, Indian reservations, other Tribal lands or other wilderness areas which are known to be inhabited by wild animals, are permitted, when on those lands, to carry and use firearms for personal protection as permitted by existing policy or as authorized by the park, refuge or area supervisor. Notwithstanding this paragraph, employees who are not on official duty may carry firearms on Departmental lands under the same conditions and in accordance with procedures and authorizations established for members of the general public.