Corn stover is an ideal biomass feedstock but the harvest and storage of this material present many challenges. Information on the fractional yield and moisture of stover grown and collected in the Upper Midwest during the typical grain harvest period was used to estimate the expected yield and moisture when utilizing various harvesting methods. At grain harvest, the ratio of stover to total crop dry mass averaged 48 % and approximately 15 %, 8 %, 21 %, and 56% of the total stover dry mass resided in the cob, husk, leaf, and stalk fractions, respectively. Total stover moisture ranged from 66% to 47% when grain moisture was less than 30%. The stalk moisture ranged from 69% to 56%, 63% to 45%, 52% to 32%, and 36% to 27% for the whole, top-three-quarters, top-half, and top-quarter of the stalk, respectively. The total stover:grain moisture ratio averaged 2.15:1. A single-pass stover and grain harvester that would collect the cob and husk plus the top-half, top-three-quarters or the entire stalk (and similar fraction of the leaves) was estimated to harvest 46%, 72%, and 100% of the available stover at a range of moistures from 49% to 33%, 57% to 38%, and 64% to 48%, respectively. Another single-pass stover and grain harvester that would collect the bottom half of the stalks, 50% of the top half of the stalk and 50% of the leaves was estimated to harvest 60% of the available stover at a range of moistures from 69% to 55%. (c) 2007 Elsevier Ltd. All rights reserved.