They raised serious concerns about the future of the national parks in a letter to the US Department of the Interior after threat emerged of further cost-cutting measures

Interior Secretary Doug Burgum is being urged by five former directors of the National Park Service to reverse course on his directives impacting national parks, writing that his orders could force superintendents to ignore their congressionally-mandated responsibilities.

The National Park Service oversees 11 sites, six trails in Pennsylvania. Visitors to these sites spend $426 million a year in and around these sites.