The City of Bainbridge Island needed to improve its understanding of geologically hazardous areas throughout the island to meet the requirements of the Growth Management Act and update and improve its critical area delineations and codes. Aspect reviewed the best available science (BAS) for geologic hazards and related development impacts. Our review focused on areas with steep slopes, high erosion and fault hazards, and high potential for liquefaction. It involved analyzing new and relevant scientific information and then using this information to revise the geologic hazard maps and codes. We used GIS methods to assimilate new, high-resolution, LIDAR-generated topographic data with existing geologic maps to predict areas of high hazard potential and to propose changes to the geologic hazard maps and codes, making them more accurate and useful to both planners and permit applicants. Code revisions were recommended and adopted by the City.