Protected areas of the United States

The protected areas of the United States are managed by an array of different federal, state, tribal and local level authorities and receive widely varying levels of protection. Some areas are managed as wilderness, while others are operated with acceptable commercial exploitation. , the 36,283 protected areas covered , or 12 percent of the land area of the United States. This is also one-tenth of the protected land area of the world. The U.S. also had a total of 787 National Marine Protected Areas, covering an additional , or 37 percent of the total marine area of the United States.
Federal level protected areas.
Federal protected areas include lands and waters owned outright ("Fee ownerships"), as well as areas that are secured by easements, leases, etc. In addition to ownership-defined areas, there are numerous overlaying policy designations that apply management protections and use conditions on all or some of individual protected areas (e.g., Wilderness Areas, National Monuments, etc.). 
, according to the United Nations Environment Programme, the U.S. had a total of 6,770 terrestrial nationally designated (federal) protected areas. Federal level protected areas are managed by a variety of agencies, most of which are a part of the National Park Service, a bureau of the United States Department of the Interior. They are often considered the crown jewels of the protected areas. Other areas are managed by the United States Forest Service, the Bureau of Land Management and the United States Fish and Wildlife Service. The United States Army Corps of Engineers is claimed to provide 30 percent of the recreational opportunities on federal lands, mainly through lakes and waterways that they manage.
The highest levels of protection, as described by the International Union for Conservation of Nature (IUCN), are Level I (Strict Nature Reserves & Wilderness Areas) and Level II (National Parks). The United States maintains 12 percent of the Level I and II lands in the world. These lands had a total area of .
Because U.S. federal protected areas include both ownership based names, and names related to overlaying policy designations, the naming system for U.S. protected areas results in some types being used by more than one agency. For instance, both the National Park Service and the U.S. Forest Service manage areas designated National Preserves and National Recreation Areas. The National Park Service, the U.S. Forest Service, and the Bureau of Land Management manage areas called national monuments. National Wilderness Areas are designated within other protected areas, managed by various agencies and sometimes wilderness areas span areas managed by multiple agencies.Those relying on U.S. protected areas data are advised to learn more about all of these conventions by reviewing the extensive PAD-US Help system. 
There are existing federal designations of historic or landmark status that may support preservation via tax incentives, but that do not necessarily convey any protection, including a listing on the National Register of Historic Places or a designation as a National Historic Landmark. States and local zoning bodies may or may not choose to protect these. The state of Colorado, for example, is very clear that it does not set any limits on owners of NRHP properties.
Federal protected area designations
International protected area designations
State level protected areas.
Every state has a system of state parks as well as many other types of protected areas (forests, reserves, refuges, recreation areas, etc.). State parks vary widely from urban parks to very large parks that are on a par with national parks. Some state parks, like Adirondack Park, are similar to the national parks of England and Wales, with numerous towns inside the borders of the park. About half the area of the park, some , is state-owned and preserved as "forever wild" by the Forest Preserve of New York. Wood-Tikchik State Park in Alaska is the largest state park by the amount of contiguous protected land; it is larger than many U.S. National Parks, with some , making it larger than the state of Delaware. Many states also operate game and recreation areas.
Local level protected areas.
U.S. counties, cities and towns, metropolitan authorities, regional park systems, recreation districts and other units manage a wide variety of local public parks and other protected areas. Some of these are little more than picnic areas or playgrounds; however, others are extensive nature reserves. South Mountain Park in Phoenix, Arizona, for example, is called the largest city park in the United States; it spans and contains of trails.