This is the first triennial Report to Congress required under Section 204 of the 2007 Energy Independence and Security Act (EISA). EISA increases the renewable fuel standards (RFS) to 36 billion gallons per year by 2022. Section 204 requires an assessment of environmental and resource conservation impacts of the RFS program. Air and water quality, soil quality and conservation, water availability, ecosystem health and biodiversity, invasive species, and international impacts are assessed, as well as opportunities to mitigate these impacts. Feedstocks compared include corn starch, soybeans, corn stover, perennial grasses, woody biomass, algae, and waste. Biofuels compared include conventional and cellulosic ethanol and biodiesel. This report is a qualitative assessment of peer-reviewed literature. This report concludes that (1) the extent of negative impacts to date are limited in magnitude and are primarily associated with the intensification of corn production; (2) whether future impacts are positive or negative will be determined by the choice of feedstock, land use change, cultivation and conservation practices; and (3) realizing potential benefits will require implementation and monitoring of conservation and best management practices, improvements in production efficiency, and implementation of innovative technologies at commercial scales.