Abstract
This paper studies the economic effects of the US National Park System, the largest national conservation entity in the world. We assemble a new dataset on the history of the system, and show that parks increase overall employment and income in the local economy. The data allows us to study several specific mechanisms. Economic effects appear to be driven by visitors, and they cannot be explained by direct government spending on park budgets or by various substitution effects. Our findings provide evidence relevant to conservation policy in the US and elsewhere.