Abstract A recent policy response to sprawl that is gaining popularity is the preservation of open space by municipal governments. This article examines the patterns of open space policy adoption using a sample of 344 suburban governments in the Philadelphia area. The empirical evidence shows that newer, high-status communities with more loss of land to development are more likely to opt for open space preservation as a policy avenue. The evidence of independent effects with respect to community age has implications for regionalism. Orfield has argued that older suburban communities are the swing vote for moving metropolitan areas toward regionalism. If the middle-aged suburbs in the Philadelphia area are needed to build a pro-regional coalition, their apparent preference for open space preservation may limit possibilities for regional reform. I argue that open space preservation on balance poses a threat to the potential for regional government by further entrenching the municipally based institutional structure of the status quo.