A statistical approach to distributed edge detection in wireless sensor networks is proposed in this research. Rather than trying to estimate the real edge of a phenomenon, the technique of edge sensor detection is adopted to determine whether a target sensor is located within the edge area or not based on information collected from its neighboring sensors. Due to the nature of wireless sensor networks, it is desirable to have a distributed algorithm that has a low computational complexity and a low data communication cost among sensors. With some reasonable assumptions and the aid of composite hypothesis testing, we propose data fusion as well as decision fusion methods for edge sensor detection to fulfill the aforementioned constraints. Numerical experiments are used to demonstrate the efficiency of the proposed algorithm.