The emerald ash borer (Agrilus planipennis Fairmaire) is an exotic insect discovered in Michigan in 2002 and which poses a serious threat to the survival of its host tree, ash (Fraxinus species). This pest species is apparently able to attack and kill both healthy and unhealthy, natural and planted ash trees. As of yet, there is no effective control method for emerald ash borer. In light of this fact, seventy-five ash monitoring plots have been established in Michigan’s Upper Peninsula during the summers of 2004 and 2005. At these plots, a variety of data was collected in order to gain baseline information on the health of the ash resource before the spread of the emerald ash borer. Data collected include tree height, diameter, crown health, vigor, damages, basal area, and relative stand age. Data from the monitoring plots in the Upper Peninsula will provide a comprehensive overview of baseline ash health at the beginning of the ash monitoring plot program. These data will enable us to evaluate the health and sustainability of the ash resource over time, accuracy of site suitability indices as predictors of ash presence, age and types of stands containing ash, and the potential impacts of emerald ash borer on forests in the Upper Peninsula of Michigan.