An apparatus, system, and method are disclosed for mapping the location of a nerve. The apparatus includes at least one stimulation module, a stimulation detection module, a distance module, and a mapping module. The stimulation module stimulates a nerve with an electrical stimulation current from at least one stimulation electrode. A stimulation detection module detects a muscle reaction resulting from stimulation of the nerve by the at least one stimulation electrode. The distance module uses information from the at least one stimulation electrode and from the stimulation detection module to calculate a distance between the at least one stimulation electrode and the nerve. The mapping module maps a location on the nerve using at least two distances calculated by the distance module and position information of the at least one stimulation electrode for each of the at least two distances calculated.