Many of the contemporary discussions of the potential for cities to address climate change overlook the historical efforts of cities to protect their residents from environmental harms. In the nineteenth and early twentieth centuries, before the emergence of the administrative state at the state and federal levels, local governments were often the first level of government to provide many Americans with environmental protection. Supplying safe drinking water was an early priority for expanding cities. With water more readily available, city governments then built sewage systems. They also built parks, established systems for collecting solid waste, and attempted to address air pollution from the combustion of coal. The historical efforts of cities, well documented by historians, emphasize that city governments can positively contribute to protecting the environment. However, these efforts also offers cautionary lessons about the limitations of relying on local governments to address large-scale problems, and help to explain the substantial federalization of environmental law in the latter twentieth century. Federalization diminished the ability of cities to innovate in the environmental field but cities still have considerable legal authority to pursue environmental policies to address contemporary challenges.