Pando (Latin for I spread), also known as the trembling giant, is a clonal colony of an individual male quaking aspen (Populus tremuloides) determined to be a single living organism by identical genetic markers and assumed to have one massive underground root system. The plant is located in the Fremont River Ranger District of the Fishlake National Forest at the western edge of the Colorado Plateau in south-central Utah, United States, around southwest of Fish Lake. Pando occupies and is estimated to weigh collectively , making it the heaviest known organism. The root system of Pando is estimated to be several thousand years old, placing Pando among the oldest known living organisms.