The largest internal organ in the human body is the liver.
The liver is located in the upper right side of the abdomen and plays a crucial role in various bodily functions. It weighs about 3 pounds on average and is responsible for metabolizing nutrients, detoxifying harmful substances, and producing bile, which helps in digestion. Additionally, the liver stores vitamins and minerals and aids in blood clotting. Its size and multifunctionality make it the most significant internal organ in terms of overall health and metabolic processes.