Changes in forest and agricultural land management practices have the potential to increase carbon (C) storage by terrestrial systems, thus offsetting C emissions to the atmosphere from energy production. This study assesses that potential for three terrestrial management practices within the state of Virginia, USA: afforestation of marginal agricultural lands; afforestation of riparian agricultural lands; and changing tillage practices for row crops; each was evaluated on a statewide basis and for seven regions within the state. Lands eligible for each practice were identified, and the C storage potential of each practice on those lands was estimated through a modeling procedure that utilized land-resource characteristics represented in Geographic Information System databases. Marginal agricultural lands' afforestation was found to have the greatest potential (1.4 Tg C yr(-1), on average, over the first 20 years) if applied on all eligible lands, followed by riparian afforestation (0.2 Tg C yr(-1) over 20 years) and tillage conversion (0.1 Tg C yr(-1) over 14 years). The regions with the largest potentials are the Ridge and Valley of western Virginia (due to extensive areas of steep, shallow soils) and in the Mid-Atlantic Coastal Plain in eastern Virginia (wet soils). Although widespread and rapid implementation of the three modeled practices could be expected to offset only about 3.4% of Virginia's energy-related CO(2) emissions over the following 20 years (equivalent to about 8.5% of a Kyoto Treaty-based target), they could contribute to achievement of C-management goals if implemented along with other mitigation measures.