The increasing demands of corn stover supply for biofuel production raise concerns about the consequences of stover removal to agricultural sustainability. The excessive harvest of corn stover could have long-term impacts on soil quality such as soil carbon content and nutrient balances. This study was conducted to evaluate the potential use of corn stover for biofuel production in relation to baseline soil organic carbon (SOC) levels in the United States for the present and future (up to 2050). We projected the future stover production based on historical corn grain yield trends for each state and estimated the harvestable stover feedstock by defining the minimum stover requirement (MSR) for maintaining the balances of SOC and major nutrients at a county level. Our preliminary analyses show that U.S. corn stover feedstock available for biofuel production could double by 2050 from the current estimate. In fact, the previous MSR values for different tillage and crop rotation systems were overestimated with the observations made mainly from the Corn Belt region where soils have very high SOC content and tend to lose carbon under cultivation. Our results suggest that the MSR data obtained from the soils with moderate levels of SOC can be used to determine the magnitude of harvestable stover feedstock without sacrificing the stover that was supposedly retained in the field to maintain SOC content; therefore, the potential of corn stover as a feedstock for U.S. biofuel production is about 40% higher than was previously expected.