My left leg has been numb for more than two days now between my hip and knee, what could be causing this?

A couple of causes.: A number of possibilities, including a spinal lesion with a pinched nerve which supplies the area between the hip and knee; a superficial nerve getting trapped near the outer & lower part of the tummy, can cause numbness ( and pain) between the hip and the knee. The medical term for this is meralgia paraesthetica. Another rare cause maybe a swelling in pelvis lying near a nerve.