Drought monitoring, assessment, forecasting, response, mitigation, and adaptation – even the very definition of drought – are dependent on the climate of the location experiencing drought. This is certainly the case for North America, where climates range from arid (southwest U.S.), semiarid and subhumid (U.S. Plains and Canadian Prairies) to humid (eastern U.S. and Canadian Maritimes) and polar (northern Canada). A Drought Indices and Definitions Study has been initiated as part of a GEO Bilateral effort to examine drought across the U.S. and Canada. Its deliverables will include a survey of the drought indices used to monitor drought, and a bibliography of research addressing the nature of drought, across the diverse climates of the continent. This paper will discuss the background of the Drought Indices and Definitions Study and summarize its current status.