Conservation of the cherished landscapes of National Parks in Britain takes place around the communities which inhabit them. Economic activities of their populations are subject to both constraints and opportunities which the statutory protection provides, with much of the development of economies displaced into their hinterlands. Analysis of spatial relationships between the three National Parks of Wales and the rest of the Wales economy has been explored using a multi-regional input-output model, based on a gravity modelling approach. This allows interregional feedback effects to be monitored and the structural characteristics of interdependence to be explored. Collectively, National Parks make a considerable contribution to the economy of Wales, in terms of incomes and employment, especially in economic sectors which either use the environment (such as agriculture) or depend on its quality for their existence (such as tourism). Comparison between each Park identifies differences in economic structure and performance, and allows the development of policy recommendations as a result.