The federal ceiling on a generator in any national park is 60 decibels measured at 50 feet. Run the same generator outside a developed area and you need a permit to run it at all. Both rules sit in one regulation, 36 CFR 2.12, read September 21, 2026.
Most campers know parks have generator hours. Far fewer know those hours are not in the CFR at all. Almost nobody knows about the permit.
What 2.12 actually says
Paragraph (a)(1) prohibits operating “motorized equipment or machinery such as an electric generating plant” in a manner “(i) That exceeds a noise level of 60 decibels measured on the A-weighted scale at 50 feet.” Generators are named in the rule. This is not someone’s interpretation.
The next clause does the real work. Even below 60 decibels, (a)(1)(ii) prohibits noise that is “unreasonable, considering the nature and purpose of the actor’s conduct, location, time of day or night, purpose for which the area was established, impact on park users, and other factors …” A quiet inverter unit at 2 a.m. can be unreasonable at 45 decibels. The number is a ceiling, not a permission slip.
Then paragraph (a)(3): “In nondeveloped areas, operating any type of portable motor or engine, or device powered by a portable motor or engine, except pursuant to the terms and conditions of a permit.”
Developed and nondeveloped are defined terms
They are not adjectives. 36 CFR 1.4, read September 21, 2026, says “Developed area means roads, parking areas, picnic areas, campgrounds, or other structures, facilities or lands located within development and historic zones depicted on the park area land management and use map.” And “Nondeveloped area means all lands and waters within park areas other than developed areas.”
So a campground is developed. Stay inside the posted hours and under the limit and you are fine. Take the same generator to a backcountry site and (a)(3) applies: portable engine, nondeveloped area, permit required. The decibel reading stops mattering, because the question is no longer how loud it is.
That catches more people than it should. Backcountry sites are exactly where someone assumes nobody is around to bother, which is the reasoning the rule is written against.
The hours are your park’s, not the CFR’s
Badlands National Park writes its own into its superintendent’s compendium, dated April 28, 2026: “Operation of electrical generators is prohibited during the hours of 8 p.m. to 8 a.m. in developed or established campgrounds or in any location within 1/4 mile of the nearest adjacent visitor. Generators must be adequately muffled and not create excessive noise. Generators are prohibited in Sage Creek Campground.”
Read that closely. The quarter-mile clause follows the nearest person, not the campground boundary, so a quiet pullout with one other rig in it is covered. One campground in the park bans generators outright. And the same compendium sets quiet hours at Cedar Pass Campground from 10 p.m. to 6 a.m., a different window from the generator window. Quiet hours and generator hours are two separate rules, and people conflate them constantly.
Yellowstone runs different numbers again, which we covered in national park camping rules.
What to do before you pull the cord
Find your park’s compendium and search it for 2.12. It is the only document that carries that park’s hours. Then read the sign at your site: where a posted sign or a ranger’s direction differs from anything you read online, including this page, the sign and the land manager win.
If you run a generator because your battery bank cannot carry the night, that is a sizing problem worth solving once. The generator sizing calculator will tell you what you need.