Pinus aristata, the Rocky Mountain bristlecone pine, is a long-living species of bristlecone pine tree native to the United States. It appears in the Rocky Mountains in Colorado and northern New Mexico, with isolated populations in the San Francisco Peaks in Arizona and the Kaibab National Forest north of the Grand Canyon. It is usually found at very high altitudes, from 7,000–13,000 feet (2,100–4,000 m), in cold, dry subalpine climate conditions, often at the tree line, although it also forms extensive closed-canopy stands at somewhat lower elevations.

The term bristlecone pine covers three species of pine tree. All three species are long-lived and highly resilient to harsh weather and bad soils. One of the three species, Pinus longaeva, is among the longest-lived life forms on Earth. The oldest of this species is more than 4,800 years old, making it the oldest known individual of any species. Many scientists are curious as to why this tree is able to live so long. In one study, they discovered that Pinus longaeva has higher levels of telomerase activity, which further slows or prevents the attrition rate of telomeres. This potentially contributes to the extended life of the bristlecone pine.