Visitors to several parks, including Yosemite in California and Zion in southern Utah were already barred from using the unmanned remotely controlled aircraft. Jonathan Jarvis, the park service director, extended the ban to the entire system, 84 million acres, in an executive order to superintendents.
Parks can continue to use drones for research, and search and rescue. In his order, Jarvis said visitors might be able to use drones in some limited circumstances with advance approval.
Jarvis said in his order that there have been at least three incidents in the past year where unmanned aircraft have disturbed visitors or wildlife.
In April, volunteers at Zion saw a herd of bighorn sheep disturbed by a drone, with the adults separating from their young. In a statement in early May on the incident, park officials said the drones are potentially harmful to birds as well as animals on the ground.
Earlier in April, a drone flew overhead as visitors watched the sunset at Grand Canyon National Park and then crashed in the canyon. Last September, rangers confiscated a drone that flew over the audience in the Mount Rushmore National Memorial Amphitheater.