Three hikers appear to have died last week from heat-related illnesses at Grand Canyon National Park, officials said Friday.

The deaths occurred during two separate incidents on June 12 and June 16 along trails in the park’s inner canyon, the park said in a news release.

The hikers were two men, ages 72 and 67, and a 68-year-old woman.

Despite aerial support and rapid response, the park said, all three were found dead on two trails — the South Kaibab Trail and the North Kaibab Trail — and taken to the Cococino County Medical Examiner’s Office.

The hikers appeared to have succumbed to heat-related illnesses, the park said.

Summer temperatures in the park’s inner canyon, which includes everything below the rim in the nearly 2,000 square mile park, can reach 109 degrees in the shade during the midday hours, the park said.

The park warned visitors Thursday to limit strenuous hiking below the rim between 10 a.m. and 4 p.m.

Data provided by the park service shows there were 34 “unintentional” deaths at the park between 2014 and 2019. That category includes heat-related fatalities, though the data does not specify how many.

The leading cause of death within the category were falls, the data shows.

An NBC News analysis of National Park Service fatality data between 2007 and 2021 found the Grand Canyon had the 20th highest death rate in the park system, well behind the deadliest — Washington State’s North Cascades National Park.

The Grand Canyon was one of the most popular national parks in the country in 2025, with more than 4 million visitors.