Miller’s death came on the first day of the federal government shutdown, which left national parks “generally” open, with limited operations and closed visitors centres.
The National Park Service said in a statement that they were investigating the incident and “park rangers and emergency personnel responded immediately.”
Miller had spent weeks solo climbing in Patagonia and the Canadian Rockies, completing a notoriously difficult ice climb called Reality Bath, which had been unrepeated for 37 years, according to Climbing magazine.
He was known affectionately as the “Orange Tent Guy”, due to his distinctive campsite at the base of El Capitan.
El Capitan, an enormous sheer granite rock face of approximately 3,000 feet (915 meters), is a major landmark in the national park and entices big-wall rock climbers from all over the world.
Miller’s death marks the third at the Californian national park this year. In June, an 18-year-old from Texas died in the park while climbing without a rope on a different formation.
And in August, a 29-year-old hiker died after being struck in the head by a large tree branch.