As part of the Geoinformatics initiative (http://www.geoinformaticsnetwork.org/), Arizona State University and the University of Texas at El Paso are working jointly to construct an integrated data system focusing on the Transition zone between the Colorado plateau and the Basin and Range province primarily in Arizona and New Mexico. This region is of fundamental significance if we are to understand the geologic evolution of southwestern North America and to address practical problems such as the effects of urbanization and dwindling water resources. Thus, it is an excellent place to construct a prototype data system for Earth Science investigations. Construction of this data system is focusing on three main efforts: 1) compilation of many large, scattered and heterogeneous earth science data sets into verified, standardized, and documented data bases; 2) construction of web-based interfaces that allow any interested party to access these data, receive robust metadata describing the data and how best to use them, and receive information on how to add data to the system via structured protocols; and 3) design and construct an extensive collection of public domain software (a toolbox) that would empower users with the capability to use and update the data in a substantial way. During this early stage of the project, we have been able to begin by amassing a number of data sets including: digital geology; terrain models; airborne- and satellite-based remotely sensed data; and gravity, magnetic, and seismic data. To narrow our focus, we have concentrated some of our higher resolution efforts on the data-rich geologically and socially important corridor from Flagstaff through Phoenix to Tucson, Arizona. However, constructing an integrated data system is a major undertaking. This ambitious project is only possible because of support from several federal and state agencies including NASA, the U. S. Geological Survey, and the Arizona Geological Survey.