36 C.F.R. § 2.15 – Pets.

(a) The following are prohibited:
1. (1) Possessing a pet in a public building, public transportation vehicle, or location designated as a swimming beach, or any structure or area closed to the possession of pets by the superintendent. This subparagraph shall not apply to guide dogs accompanying visually impaired persons or hearing ear dogs accompanying hearing-impaired persons.
2. (2) Failing to crate, cage, restrain on a leash which shall not exceed six feet in length, or otherwise physically confine a pet at all times.
3. (3) Leaving a pet unattended and tied to an object, except in designated areas or under conditions which may be established by the superintendent.
4. (4) Allowing a pet to make noise that is unreasonable considering location, time of day or night, impact on park users, and other relevant factors, or that frightens wildlife by barking, howling, or making other noise.
5. (5) Failing to comply with pet excrement disposal conditions which may be established by the superintendent.
(b) In park areas where hunting is allowed, dogs may be used in support of these activities in accordance with applicable Federal and State laws and in accordance with conditions which may be established by the superintendent.
(c) Pets or feral animals that are running-at-large and observed by an authorized person in the act of killing, injuring or molesting humans, livestock, or wildlife may be destroyed if necessary for public safety or protection of wildlife, livestock, or other park resources.
(d) Pets running-at-large may be impounded, and the owner may be charged reasonable fees for kennel or boarding costs, feed, veterinarian fees, transportation costs, and disposal. An impounded pet may be put up for adoption or otherwise disposed of after being held for 72 hours from the time the owner was notified of capture or 72 hours from the time of capture if the owner is unknown.
(e) Pets may be kept by residents of park areas consistent with the provisions of this section and in accordance with conditions which may be established by the superintendent. Violation of these conditions is prohibited.
(f) This section does not apply to dogs used by authorized Federal, State and local law enforcement officers in the performance of their official duties.