The state of stress directly influences several key aspects of unconventional oil and gas development, including both the ideal orientation for drilling horizontal wells and the effectiveness of hydraulic fracturing stimulations. Over the past several years, the Stanford Stress Group has collected more than 600 new maximum horizontal principal stress (SHmax) orientations across North America as well as 1900 hundred estimates of the relative magnitude of the three principal stresses utilizing earthquake focal plane mechanisms. In this presentation, we will discuss these “new generation” stress maps, paying particular attention to the stress state in major unconventional oil- and gas-producing basins.