A basic modular exploration sequence which includes a carefully balanced selection of geological, geochemical, and geophysical modules is developed for geothermal prospecting in the eastern Basin and Range. The cost per square mile for application of this exploration architecture is $461.00. If one were to expand this basic system to include virtually all techniques being routinely employed in geothermal prospecting today, then the cost per square mile would increase to $790.00. This latter expenditure rate is difficult to justify, but some increase above the $461.00 basic cost appears to be warranted to make exploration costs about equal to land acquisition costs and model-test drilling costs. Total costs per discovery appear to range from $6M to $27M depending upon assumptions, when the costs of exploring for dry prospects are included in the costs of the discoveries. Development and operating costs are not included in the analysis. The basic exploration architecture described here is compared with others previously advanced in the literature. If a common basic is used for computing costs of individual exploration modules, then there is no great cost disparity between any of the architectures reviewed.