Results/Conclusions: In both cities, the dominant land-use legacy is the agriculture-to-urban transition. Former agricultural soils have higher carbon and nutrient content that urban soils with non-agricultural histories. Because of economic legacies, we find higher biodiversity in wealthier neighborhoods (termed the “luxury effect” by CAP and an “ecology of prestige” by BES). Both cities have seen reduced sprawl in recent decades, but only in Baltimore is this driven by policy (an urban-rural development boundary). Baltimore is characterized by abandonment of the urban core while in Phoenix abandonment, driven by massive foreclosures during the Great Recession, is widely distributed and heterogeneous. Both types of abandonment have parcel-scale ecological implications. In more stable parcels, we have found that residents of both cities make very different decisions about their back yards versus front yards. Beyond residential parcels, we have documented multi-decadal hydrologic changes in both cities. In Baltimore, degraded and broken stormwater and wastewater infrastructure has created major institutional challenges, some of which are being solved by new ecological infrastructure. In Phoenix, changes in stormwater infrastructure over the last 50 years have strongly influenced hydrologic and nutrient retention. Finally, neighborhood median income strongly controls bird community composition in both cities, and mosquito prevalence in Baltimore.