As use of geospatial technologies has increased in the workplace, so has interest in using these technologies in the K-12 classroom. Prior research has identified several reasons for using geospatial technologies in the classroom, such as developing spatial thinking, supporting local investigations, analyzing changes in the environment, and interesting students in technology and geography. The National Research Council (NRC) advocates spatial thinking instruction across the K-12 curriculum and instruction in geospatial technologies, such as geographic information systems (GIS), is one way to increase understanding in spatial thinking. Many educators agree that GIS can be a useful tool for student learning; however, if GIS is going to be successfully integrated into the classroom, many issues need to be addressed, including those related to professional development. Many of the characteristics of effective professional development apply to professional development in geospatial technologies but researchers continue to identify best practices. The professional development objectives for the NSF ITEST (Innovative Technology Experiences for Students and Teachers) program at the University of Kentucky were threefold: (1) to increase knowledge of geospatial technologies, including GIS, GPS, and remote sensing; (2) to develop spatial thinking; and (3) to apply that knowledge to community-based natural resource investigations, a localized form of project-based learning (PBL). The UK team hypothesized that the unique components of this professional development program would be an effective way to increase teachers' knowledge of new technologies and spatial thinking and to instruct teachers how to apply that knowledge to community-based investigations. (Contains 12 tables.)