The source of Deep Creek is at an elevation of , at the head of Little Green Valley in the San Bernardino Mountains. It initially flows southwest, through the communities of Arrowbear and Running Springs, before turning north. It is joined by Hooks Creek from the west; a dam on Little Bear Creek, a tributary of Hooks Creek, forms Lake Arrowhead. A short distance downstream is Aztec Falls, a popular swimming area at a waterfall along Deep Creek.