GIS can be a powerful tool for analyzing and displaying data about the environment. In many cases rich sources of data are available from federal, state, and local government agencies and private sources. In using GIS data for public health research, it is important to have data with sufficient detail to study the exposures of interest. Research on the impact of the environment on physical activity suggests that the characteristics of the environment within an easy walk from people's homes, schools, and work might influence their level of physical activity. Obtaining the detailed, neighborhood level GIS data necessary to study the role of the environment in physical activity can be challenging. In this study, we combined existing data together with newly created data to characterize the campuses and neighborhoods around 10 public schools in the metropolitan Boston area. This website illustrates the steps we took using ArcGIS 9.1 to accomplish this task.