Spatially-distributed forest biomass components are essential to understand carbon cycle and the impact of biomass burning emissions on air quality. We estimated the density of forest biomass components (foliage biomass, branch biomass, and aboveground biomass) at a spatial resolution of 1 km across the Contiguous United States using foliage-based generalized allometric models and Moderate-Resolution Imaging Spectroradiometer (MODIS) land data. The foliage biomass for each forest type was calculated from MODIS leaf-area indices, land cover types, and vegetation continuous fields. The foliage-based models were developed using available diameter-based allometric equations and used to estimate branch biomass and aboveground biomass. The resultant aboveground biomass density matches well with the data from Forest Inventory and Analysis program at both state and pixel levels.