RMNP closed at the request of the local mayor and health department. 

On March 20, Estes Park Mayor Todd Jirsa put out a plea to Secretary of the Interior David Bernhardt to close Rocky Mountain National Park's gates in the face of impending COVID-19 cases. The mayor made the request of the federal government, worried that too many visitors could bring with them new coronavirus cases (the first case in Estes Park was confirmed on March 19), as well as overwhelm the mountain town's medical infrastructure. 

"The Park currently remains open without fees. The Department of Interior’s current promotions are driving visitors to parks and communities like Estes Park. This increase in visitation is compounded by spring break travel and the recent closure of ski resorts elsewhere in our state," said the letter. " We have an older, high-risk population with many retirees, and limited critical resources. Some of our businesses are closing and others are on restrictions to comply with public health orders.
Medical and emergency services, as well as basic supplies like groceries must be available to meet the needs of our community at this time. Estes Park is not in a position to support the potential needs of extra guests at this time."

Just a few hours after receiving the request, the National Park Service responded by closing RMNP indefinitely. As of 7 p.m. on Friday, March 20, 2020, Rocky Mountain National Park is closed to all park visitors until further notice. This closure will be in effect 24 hours a day, 7 days a week, and there will be no access permitted to any area of the park. 

"The health and safety of our visitors, employees, volunteers, and partners at Rocky Mountain National Park is our number one priority. The National Park Service (NPS) is working with the federal, state, and local authorities to closely monitor the novel coronavirus (COVID-19) situation. We will notify the public when we resume full operations and provide updates on this site and our social media channels," said NPS.  

RMNP joins Yosemite as the two National Parks that have shut down so far. All other National Parks and Colorado State Parks remain open at the time of this writing.