Unfortunately, it's not that simple to figure out. A few points:
Landing an airplane in National Parks or National Wildlife Refuges in the Lower 48 states is GENERALLY prohibited. There are exceptions, but very few. For example, you can land a seaplane within the Charles M. Russell National Wildlife Refuge on floats, but only at the town boat launch site at Fort Peck. etc.
But, in Alaska, landing an airplane within the boundaries of a National Park or Wildlife Refuge is GENERALLY permitted. There are also exceptions there, where aircraft operations may be prohibited, such as the Kenai NWR canoe trail lakes, where seaplanes are prohibited, but that's a very small portion of the refuge.
As to where these regulations are found, they will generally be listed in the agency regulations. For example, 16 USC CFR 50 contains the general regulations for National Wildlife Refuges. Here's the section from that regulation regarding the operation of aircraft:
§ 27.34 Aircraft.
The unauthorized operation of air-
craft, including sail planes, and hang
gliders, at altitudes resulting in har-
assment of wildlife, or the unauthor-
ized landing or take-off on a national
wildlife refuge, except in an emer-
gency, is prohibited. National wildlife
refuge boundaries are designated on up-
date FAA aeronautical charts.
Since the Fish and Wildlife Service does have search and seizure authority, the MAY seize an aircraft that illegally landed on a Refuge. If that were the case, the US District Court would eventually either return the aircraft to the owner or forfeit it to the government.
BUT, again, this regulation applies ONLY to refuges in the lower 48.
In Alaska, the requirement to make all refuges and parks/monuments open to aircraft landings was specified in the Alaska National Interest Conservation Act (ANILCA), which went into effect in 1980. That Act established or re-established ALL National Wildlife Refuges and National Parks in Alaska, and one provision was that aircraft landings are to be permitted, EXCEPT as necessary for management purposes. Here's a web link for information on specific areas:
https://www.faa.gov/about/office_org/he ... ies/parks/.
But, understand that there are Refuge and Park specific regulations as well. Those were promulgated for some specific reason....a closure of the wilderness canoe route in the Kenai NWR, for example. SO you also have to look at Refuge and Park specific regulations.
Then there's National Forest lands and BLM managed lands...... Again, in Alaska, those lands are almost universally open to aircraft landings. Again, helicopters require special permits, just like parks and refuges.
But, in the lower 48, I think you'll find that GENERALLY, most forests and BLM lands prohibit aircraft landings. Again, I'd go to the specific unit and ask them. And, by the way, ask them for the regulation citation.....a few managers have been known to quote theory as policy.
As to Indian Reservations, don't even think about going there, unless you are landing at a public airport, on privately owned lands within the reservation AND have an invitation. Reservations in the lower 48 are sovereign nations, which means state law may or may not apply there, but basically if you land your plane on their land, they may keep it, they may disassemble it and get it off the reservation, etc. Some folks in Minnesota found this out the hard way a few years ago. Got the plane back, but.....
So, it's complicated, unfortunately. The regulations are generally in the agency's "organic act" and regulations promulgated under that Act.
Good luck.
MTV