Maps are an essential starting point for large-scale assessment of biodiversity patterns and conservation priorities. We are involved in both global- and regional-scale efforts. At the global scale, we are working on cumulative threat analyses for watersheds that incorporate a wide variety of threat types (in collaboration with many colleagues from the Global Water System Project and DIVERSITAS-Freshwater). We are also synthesizing all available data on biodiversity patterns in large lakes (in collaboration with Yvonne Vadeboncoeur and Jake Vander Zanden), and contributing to a new effort to comprehensively map the global distribution of freshwater biodiversity (GEO BON-Freshwater). At the regional scale, I co-lead the Great Lakes Threat Mapping Project with David Allan and Ben Halpern. This project seeks to merge all existing data on threats to the Laurentian Great Lakes, including chemical pollutants, habitat alteration, invasive species, eutrophication, and over-fishing. Our goal is to generate maps of aggregate threat that can be used to guide either place-based or stressor-based approaches to prioritizing restoration and conservation efforts. This project is particularly timely in light of the unprecedented Great Lakes Restoration Initiative.