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. As of 2015, the 25,800 protected areas covered 1,294,476 km2 (499,800 sq mi), or 14 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 1,271,408 km2 (490,893 sq mi), or 12 percent of the total marine area of the United States.