Using Silicon Valley as a case study, this dissertation examines how activists influenced by the environmental movement reconfigured urban culture in the American West. *Machines in the Valley* argues that the spatial influences of the region's urban development gave rise to modern environmentalism that arose to criticize growth, but along the way failed to ultimately shape growth policies. While high technology sought to introduce a new urban form predicated on "clean and green" industries and an environmental urbanism, the premise of "clean" industry proved elusive.