National Park Service
The National Park Service (NPS) is part of the United States Department of the Interior. The National Park Service looks after many natural landscapes and historic and archaeological places and buildings. Millions of people from around the world visit the national parks. The National Park Service helps keep these parks in order. 
The National Park Service has two main jobs. One is to protect America’s national parks. The other is to help visitors enjoy them. Some people think these two jobs conflict with each other.
They say some of the problems of the parks are the result of too many people visiting them. For example, the many vehicles in national parks cause pollution and road damage. And the many visitors cause water and waste systems to have to work hard.
Some national parks cost money to enter. But they're generally affordable. And parks that charge entry fees must share the money with parks that do not. That means they cannot keep all the money for things like repairs and improvements.
For years, the Park Service has said it does not have enough money to operate at its best. Sometimes visitors protest about conditions in the parks. For example, they say some roads and places to sleep have not been repaired as needed. Critics of the system say many parks lack enough employees.
Money to support America's national parks comes from the federal government and visitors. It also comes from businesses and individuals through the National Park Foundation. Congress established this organization in 1967. The job of the foundation is to gather private support for America's national parks.
In the nation’s capital, for instance, the Target Corporation provided money to help restore the Washington Monument. Another example is Kodak. That company supports photo competitions at national parks. And there is much to photograph.
The National Park received additional funding in 2020. This means visitors get extra one day free visit to the parks every August. 
- "THIS IS AMERICA — National Park System - 2003-08-26". VOA. Retrieved 2020-08-18.
- Budget Justifications and Performance Information, Fiscal Year 2008, National Park Service
- Tate, Curtis. "National parks are getting more funding: What it means for visitors (including an extra free day)". USA TODAY. Retrieved 2020-08-18.