As a part of the Invasive Mussel Collaborative (IMC) September, 2019 meeting, an ad hoc group of 12 IMC members met to initially start the process of developing coastal site priorities for potential dreissenid mussel experimental control. Initial tasks included 1) a review information on where dreissenids are impacting Great Lakes resources, 2) identification of criteria for evaluating sites based on this information and other considerations, and 3) development of a process for prioritizing sites for potential management activities. During the working session, participants discussed a number of initiatives that might be useful for consideration during the prioritization process, including the GLFC lake committee environmental priorities, coastal assessments, and inventories, and developed a list of potential criteria for consideration in the prioritization process. A number of criteria were proposed for consideration including important fish spawning and nursery habitats, commercial pathways, water temperature effects on control efficacy, accessibility for control actions, long-term monitoring/assessment, terrestrial species impacts, native unionid refugia, historical/cultural sites, water quality, parks and protected areas, harmful algal blooms, and areas where phosphorus is impacting ecological function. The IMC meeting participants also discussed other issues that were identified in the IMC Strategy including ecological impacts of control, level of control needed (site-specific vs regional control). Subsequently, the participants evaluated the list of potential criteria identified and categorized them as either primary screening criteria for identifying priority sites or secondary considerations, and identified potential data sources or needs to support the criteria development. The ad hoc group agreed to put together the suggested criteria into an evaluation matrix for review and refinement for the development of a coastal site prioritization process.