If you are interested in exploring park ranger work, you may wish to apply for part-time or seasonal work in national, state, county, or city parks. Such workers usually perform maintenance and other simple tasks, but they have opportunities to observe park rangers and talk with them about their work. You might also choose to work as a volunteer. Many park research activities, study projects, and rehabilitation efforts are conducted by volunteer groups affiliated with universities or conservation organizations, such as the Student Conservation Association. These activities can provide insight into the work done by park rangers.

Park rangers have a wide variety of duties that range from conservation efforts to bookkeeping. Their first responsibility is, however, safety. Rangers who work in parks with treacherous terrain, dangerous wildlife, or severe weather must make sure hikers, campers, and backpackers follow outdoor safety codes. They often require visitors to register at park offices so that rangers will know when someone does not return from a hike or climb and may be hurt. Rangers often participate in search-and-rescue missions for visitors who are lost or injured in parks. In mountainous or forested regions, they may use helicopters or horses for searches.

Rangers also protect parks from inappropriate use and other threats from humans. They register vehicles and collect parking and registration fees, which are used to help maintain roads and facilities. They enforce the laws, regulations, and policies of the parks, patrolling to prevent vandalism, theft, and harm to wildlife. Rangers may arrest and evict people who violate these laws. Park protection efforts include keeping jeeps and other motorized vehicles off sand dunes and other fragile lands. They make sure visitors do not litter, pollute water, chop down trees for firewood, illegally hunt, or start unsafe campfires that could lead to catastrophic forest fires. When forest fires do start, rangers often assist with the dangerous, arduous task of putting them out and evacuation.

Park rangers also manage the parks' natural resources. An important aspect of this responsibility is the care of native species and the control of exotic (non-native) species within the parks. Duties may include conducting scientific research, as well as disseminating information about the reintroduction of native animal populations and the protection of the natural habitat that supports the animals.

Rangers also help with conservation, research, and ecology efforts that are not connected to visitors' use of the park. They may study wildlife behavior patterns, for example, by tagging and following certain animals. In this way, they can chart the animals' migration patterns, assess the animals' impact on the park's ecosystem, and determine whether the park should take measures to control or encourage certain wildlife populations.

Some rangers study plant life and may work with conservationists to reintroduce native or endangered species. They measure the quality of water and air in the park to monitor and mitigate the effects of pollution and other threats from sources outside park boundaries. Through these efforts, rangers contribute to the growing body of research regarding our natural world.

In addition, park rangers help visitors enjoy and experience parks. In historical and other cultural parks, such as the Alamo in San Antonio, Independence Hall in Philadelphia, and the Lincoln Home in Springfield, Illinois, rangers give lectures and provide guided tours explaining the history and significance of the site. In natural parks, they may lecture on conservation topics, provide information about plants and animals in the park, and take visitors on interpretive walks, pointing out the area's flora, fauna, and geological characteristics. At a Civil War battlefield park, such as Gettysburg National Military Park in Pennsylvania or Vicksburg National Military Park in Mississippi, they explain to visitors what happened at that site during the Civil War and its implications for our country.

Park rangers are also indispensable to the management and administration of parks. They issue permits to visitors and vehicles and help plan the recreational activities in parks. They help in the planning and managing of park budgets. They keep records and compile statistics concerning weather conditions, resource conservation activities, and the number of park visitors.

Many rangers supervise other workers in the parks who build and maintain park facilities, work part time or seasonally, or operate concession facilities. Rangers often have their own park maintenance responsibilities, such as trail building, landscaping, and caring for visitor centers.

In some parks, rangers are specialists in certain areas of park protection, safety, or management. For example, in areas with heavy snowfalls and a high incidence of avalanches, experts in avalanche control and snow safety are designated snow rangers. They monitor snow conditions and patrol park areas to make sure visitors are not lost in snowslides.