This paper provides a flexible model of resource extraction, such as deforestation, and derives the optimal conservation contract. When property rights are “strong” and districts are in charge of extracting their own resources to get revenues, conservation in one district benefits the others since the reduced supply raises the sales price. A central authority would internalize this positive externality and thus conserve more. When property rights are instead weak and extraction is illegal or costly control, conservation in one district increases the price and thus the profit from illegally depleting the resource in the other districts. The externality from conservation is then negative, and centralization would lead to less conservation. We also derive the optimal conservation contract, and we explain when the principal, who values conservation, benefits from contracting with the districts directly even when contracting with a central authority would have led to more conservation, and vice versa.