Marginal land now devoted to growing harvested crops may be better suited to other land uses such as biodiversity enhancement and carbon sequestration. However, farmers are not encouraged to explore the development of these opportunities due largely to subsidized federal crop insurance (FCI). This study examined FCI outcomes from 2013 to 2017 in 69 Coastal Plain counties of North Carolina and South Carolina. The loss ratio (total crop indemnities paid/total insurance premiums paid) was used to identify 21 counties with high-risk agriculture. Then an index of conservation opportunity was calculated for each county using the loss ratio, insurance subsidy, and an estimate of natural capital (i.e., renewable or nonrenewable natural resources that can provide benefits to humans). Where marginal farmland is surrounded by forest and natural capital is high, the index will identify counties currently supported by FCI that more quickly and completely incorporate the full range of ecological dynamics and biological diversity when farming is abandoned. The top 10 counties for conservation opportunity, with the exceptions of Scotland County, North Carolina, and Marion County, South Carolina, were located in the outer Coastal Plain or coastal zone where natural capital is high. Transitioning land use from harvested crops to biodiversity enhancement or carbon sequestration will require bold changes in agricultural policies and subsidies so that income streams to farmers are maintained while novel ecological targets are met.