Although a considerable number of studies have examined the effectiveness of growth management programs in curbing sprawl and increasing aggregate densities, less attention has been paid to understanding how these noted density improvements are realized. In this paper, we assess the mechanisms that underlie changes in aggregate population densities and empirically examine detailed density changes under various growth management regimes in the U.S. Our county-level statistical analysis using recent U.S. Census products and land use change data sets, finds that: a) states with proactive growth management programs do tend to experience relative density gains, but not in jurisdictions with restrictive local land use regulations and b) the marginal density gains appear to be attributable in large part to smaller housing vacancy rates and housing price escalations. Not surprisingly, our findings suggest that local structures are critical for achieving desired outcomes. Given the critical role of local action, the realization of compact development requires a tightly woven and integrated policy that not only makes logical sense at state levels, but can be followed and implemented at the local level.