This chapter presents an overview of the development, capabilities, and utilization of geographic information systems (GIS). There are nearly an unlimited number of applications that are relevant to GIS because virtually all human interactions, natural and man-made features, resources, and populations have a geographic component. Everything happens somewhere and the location often has a role that affects what occurs. This role is often called spatial dependence or spatial autocorrelation, which exists when a phenomenon is not randomly geographically distributed. GIS has a number of key capabilities that are needed to conduct a spatial analysis to assess this spatial dependence. This chapter presents these capabilities (e.g., georeferencing, adjacency/distance measures, overlays) and provides a case study to illustrate how GIS can be used for both research and planning. Although GIS has developed into a relatively mature application for basic functions, development is needed to more seamlessly integrate spatial statistics and models.The issue of location, especially the geography of human activities, interactions between humanity and nature, and the distribution and location of natural resources and features, is one of the most basic elements of scientific inquiry. Conceptualizations and physical maps of geographic space have existed since the beginning of time because all human activity takes place in a geographic context. Representing objects in space, basically where things are located, is a critical aspect of the natural, social, and applied sciences. Throughout history there have been many methods of characterizing geographic space, especially maps created by artists, mariners, and others eventually leading to the development of the field of cartography. It is no surprise that the digital age has launched a major effort to utilize geographic data, but not just as maps. A geographic information system (GIS) facilitates the collection, analysis, and reporting of spatial data and related phenomena. The capabilities of GIS are much more than just mapping, although map production is one of the most utilized features. GIS applications are relevant in a tremendous number of areas ranging from basic geographic inventories to simulation models.This chapter presents a general overview of geographic information system topics. The purpose is to provide the reader with a basic understanding of a GIS, the types of data that are needed, the basic functionality of these systems, the role of spatial analysis, and an example in the form of a case study. The chapter is designed to provide advanced students and experts outside of the field of GIS sufficient information to begin to utilize GIS and spatial analytic concepts, but it is not designed to be the sole basis for becoming a GIS expert. There is a tremendous level of sophistication related to the digital cartographic databases and manipulation of those databases underlying the display and use of GIS that is more appropriately a part of geographic information science (i.e., basic research issues associated with geographic data including technical as well as theoretical aspects such as the impact on society [1]) rather than being relevant to this chapter. The utilization of GIS for conducting spatial analysis is the guiding theme for the chapter.