What is the largest living organism by area?

The largest living organism by area is a fungus located in the Malheur National Forest in Oregon, USA. Armillaria ostoyae, commonly known as the honey fungus, spans over 2,400 acres (970 hectares) and is considered a single organism because it shares the same genetic structure. This organism spreads underground in the form of mycelial networks, slowly overtaking trees and vegetation. It is estimated to be thousands of years old and continues to grow.