Abstract The preservation of open spaces has become an important policy topic in many regions. Policy tools that have been used include: cluster zoning; transferable development rights; proposed land taxes to fund purchases of remaining open spaces; and private organizations that buy land. This paper develops a theoretical model of how different types of open spaces are valued by residential land owners living near these open spaces, and then, using a hedonic pricing model, tests hypotheses concerning the extent to which these different types of open spaces are capitalized into housing prices. The empirical results from Howard County, a rapidly developing county in Maryland, USA, show that “permanent” open space increases near-by residential land values over three times as much as an equivalent amount of “developable” open space. This methodology can be used to help inform policy decisions concerning open space preservation, such as effectively targeting certain areas for preservation, or as a means of creative financing of the purchase of conservation easements, through the increase in property taxes, resulting from the associated increase in property values.