The use of nitriding to improve a component’s resistance to wear, fatigue, and corrosion continues to increase across the industry. However, for nitrided components, no universally accepted definition of “case depth” is available to allow the comparison of different nitriding processes, cycles, and materials. This study documents currently published methods of specifying and determining case depth for nitrided components, and evaluates the reported case depth of multiple materials and cycles in an effort to determine an optimal and robust “universal” method of reporting case depth. After completing this exercise, it appears that the optimal “universal” method of specifying and reporting the case depth for a nitrided component is to report the depth at which a Vickers microhardness traverse crosses a threshold which is 50HV greater than the material hardness below the nitrided case.