Abstract: As increasing numbers of grassroots organizations use geographic information systems (GIS), the debate grows on whether or how they should adopt the technology. However, we know little about the GIS implementation processes within these organizations. This paper presents the results of five-year case study research of GIS implementation patterns by grassroots conservation organizations in northern California. In the paper I investigate alternatives that four cases have found to traditional models of GIS implementation and factors of successful usage. I also explore how these strategies might extend the traditional views of implementation and inform other institutional users, such as local governments, with innovations in GIS implementation and use.