The National Park System was initiated by the United States Congress in 1872, during the administration of President Ulysses S. Grant, when Yellowstone National Park was created. This landmark act established Yellowstone as "a public park or pleasuring ground for the benefit and enjoyment of people."
On August 25, 1916, President Woodrow Wilson signed an act creating the National Park Service as a federal bureau within the Department of the Interior. Its mission is to preserve, protect, and manage the national, cultural, historical, and recreational areas of the National Park System. In 1916, the park system contained less than 1 million acres. Today the country's national parks cover nearly 84 million acres of mountains, plains, deserts, swamps, historic sites, lakeshores, forests, rivers, battlefields, memorials, archaeological properties, and recreation areas.
- Active and Contemplative Religious Sisters and Brothers
- Adventure Travel Specialists
- Agricultural Scientists
- Air Quality Engineers
- Airport Service Workers
- Ambassadors
- Amusement Park Workers
- Anthropologists
- Aquarists
- Arborists
- Archaeologists
- Archivists
- Artists
- Aviation Safety Inspectors
- Bailiffs
- Bank Examiners
- Bicycle Mechanics
- Biochemists
- Bioenergy/Biofuels Workers
- Biofuels Processing Technicians
- Biofuels Production Managers
- Biofuels/Biodiesel Technology and Product Development Managers
- Biologists
- Biomass Plant Technicians
- Biomass Power Plant Managers
- Book Conservators
- Border Patrol Agents
- Botanists
- Brownfield Redevelopment Specialists and Site Managers
- Business Managers
- Campaign Workers
- Chemists
- Chief Sustainability Officers
- Chimney Sweeps
- City Managers
- Civil Engineers
- Congressional Aides
- Conservators and Conservation Technicians
- Construction Inspectors
- Corporate Climate Strategists
- Cruise Ship Workers
- Cryptographic Technicians
- Customs Officials
- Demographers
- Deputy U.S. Marshals
- Directors of Corporate Sponsorship
- Directors of Fund-Raising
- Directors of Volunteers
- Ecologists
- Economists
- Education Directors and Museum Teachers
- Energy Conservation Technicians
- Energy Consultants
- Engineers
- Environmental Economists
- Environmental Education Program Directors
- Environmental Engineers
- Environmental Lawyers
- Environmental Lobbyists
- Environmental Planners
- Environmental Restoration Planners
- Environmental Scientists
- Environmental Technicians
- EPA Special Agents
- Ethnoscientists
- Exhibit Designers
- FBI Agents
- Federal and State Officials
- Fish and Game Wardens
- Flight Attendants
- Foreign Service Officers
- Foresters
- Forestry Technicians
- Fraud Examiners, Investigators, and Analysts
- Fund-Raisers
- Futurists
- Gallery Owners and Directors
- Gaming Occupations
- General Maintenance Mechanics
- Geological Technicians
- Geologists
- Geophysicists
- Grant Coordinators and Writers
- Green Builders
- Green Hotel/Resort Ecomanagers
- Green Products Manufacturers
- Green Transportation Careers
- Groundwater Professionals
- Hazardous Waste Management Specialists
- Hazardous Waste Management Technicians
- Health and Regulatory Inspectors
- Heating and Cooling Technicians
- Historians
- Historic Preservationists
- Horticultural Inspectors
- Horticultural Technicians
- Hosts/Hostesses
- Hydropower and Marine Energy Industry Workers
- Inbound Tour Guides
- Industrial Ecologists
- Intelligence Officers
- Interpreters
- Janitors and Cleaners
- Land Acquisition Professionals
- Land Trust or Preserve Managers
- Landscape Architects
- Landscapers and Grounds Managers
- Librarians
- Lifeguards and Swimming Instructors
- Lobbyists
- Logging Industry Workers
- Marine Biologists
- Methane/Landfill Gas Collection System Operators
- Methane/Landfill Gas Generation System Technicians
- Microbiologists
- Military Recruiters
- Military Workers, Enlisted
- Molecular and Cellular Biologists
- Museum Attendants
- Museum Directors and Curators
- Museum Technicians
- Music Venue Owners and Managers
- Naturalists
- Nonprofit Social Service Directors
- Occupational Safety and Health Workers
- Oceanographers
- Paper Processing Workers
- Park Rangers
- Parking Attendants
- Pilots
- Plumbers and Pipefitters
- Policy Analysts
- Political Scientists
- Press Secretaries and Political Consultants
- Property and Real Estate Managers
- Proposal Managers
- Public Interest Lawyers
- Public Opinion Researchers
- Public Relations Specialists
- Rabbis
- Range Managers
- Real Estate Developers
- Recreation Workers
- Recycling and Reclamation Workers
- Recycling Coordinators
- Regional and Local Officials
- Renewable Energy Careers
- Renewable Energy Engineers
- Reservation and Ticket Agents
- Resort Workers
- Restaurant and Food Service Managers
- Roman Catholic Priests
- Secret Service Special Agents
- Security Consultants and Guards
- Ship's Captains
- Ski Resort Workers
- Social Workers
- Soil Conservationists and Technicians
- Soil Scientists
- Spa Attendants
- Spa Managers
- Sports Facility Managers
- Sports Instructors and Coaches
- Stadium Ushers and Vendors
- Stationary Engineers
- Strength and Conditioning Coaches
- Tour Guides
- Traffic Engineers
- Translators
- Transportation Planners
- Travel Agents
- Urban and Regional Planners
- Wastewater Treatment Plant Operators and Technicians
- Water/Wastewater Engineers
- Wood Science and Technology Workers
- Yoga and Pilates Instructors
- Zoo and Aquarium Curators and Directors
- Zookeepers
- Zoologists