The objective of this study was to investigate roll press compaction of coarsely ground corn stover and native perennial grasses to produce compacted products with a bulk density of at least 240 kg m(-3) for effective truck transport. A pilot-scale roll press compaction machine (520.7 mm roll diameter and 127.0 mm roll width) was used to compress corn stover and perennial grasses (moisture contents of 10% to 18% wet basis) ground in a tub-grinder with three round-hole screen opening sizes (25.4, 76.2, and 127.0 mm). Bulk density of compacted materials (i.e., compacts) ranged from 263 kg m (-3) to 365 kg m(-3) for the roll compaction forces of 214-534 kN. Durability (tumbling test) of compacts ranged from 61% to 92%. Specific energy consumption (excluding no-load machine energy) for the roll press compaction ranged from 19 MJ Mg (1) to 339 MJ Mg (1). The results from this study would be useful for developing a biomass supply logistics system involving coarse-grinding followed by roll press compaction of biomass bales. (C) 2013 Elsevier Ltd. All rights reserved.