The economic competitiveness of cellulosic ethanol production is highly dependent on feedstock cost, which constitutes 35-50% of the total ethanol production cost, depending on geographical factors such as biomass species, yield, location, climate, local economy, as well as the types of systems used for harvesting, collection, preprocessing, and transportation.  Consequently, as the deployment of cellulosic ethanol biorefineries approaches, feedstock cost and availability are the driving factors that influence the selection of pioneer biorefinery locations, and these same factors will largely control the rate at which this industry grows. Due to geographic variability and complex distributed supply system dynamics, estimating feedstock costs and supplies has been a major source of uncertainty.  This paper presents an integrated analysis of the feedstock supply system that provides an understanding of the impacts these issues have on feedstock costs delivered to the biorefinery. A number of supply system design scenarios will be presented, starting with a pioneer supply system design case as a demonstration of the current state of technology.  Based on this pioneer design, advanced scenarios were developed to determine the key cost barriers and to identify the supply system improvements and technology advancements necessary for achieving a design case cost target.  In addition, further analyses were performed to evaluate supply system designs for other geographic regions as well as for variety of feedstocks.  This analysis revealed how supply system costs can vary substantially for different regions and for different feedstock resources.