The largest and longest bone in the human body is the femur, and it is located in the upper leg. The femur connects to the knee at one end and fits into the hip socket at the other.
The femur is made up of three parts, which are the head, body and lower extremity. The length of the femur averages 26 percent of a person's overall height, so it's not surprising that the femur is also the strongest bone in the human body.
More than 40 muscles and ligaments are attached to and depend on the femur bone for functioning. The femur is also referred to as the thigh bone as it is the only bone in the thigh.