The largest muscle in the human body is the gluteus maximus. The gluteus maximus is located in your buttocks and its size directly corresponds to the important role it has in your everyday life.It’s main function is to keep your body erect and straight.f by strongest you mean “ability to exert a force on an external object”, then a human’s strongest muscle is his or her ‘ masseter ‘ muscle. The masseter muscle is a thick muscle in the cheek and is located at the back of the jaw.