Each year the Superintendent, under discretionary authority, establishes certain amendments to the Code of Federal Regulations (36 CFR 1.7(b)) that designate certain closures, permit requirements and other restrictions in the park. That document is available as a PDF file here.
The law governing possession of firearms inside a national park changed on February 22, 2010.
Visitors may possess firearms within a national park unit provided they comply with federal, state, and local laws.
The role of the responsible gun owner is to know and obey the federal, state, and local laws appropriate to the park they are visiting.
Please remember that federal law prohibits firearms in certain park facilities and buildings. These places are marked with signs at public entrances.
Home page: http://az.gov/
Last updated: May 15, 2020