Broadly scaled information about the extent and character of U.S. grazing lands provides a context for considering the more finely scaled processes driving carbon (C) cycling on grazing lands. Such information also is necessary for estimating the potential for grazing lands to sequester atmospheric C at local, regional, national, or global scales, relative to such other general land cover/use categories as cropland and forest. The terms “broad” and “fine” scale appear often throughout this chapter, and we define them as did Turner and Gardner (1991). Broad scale implies coarse spatial resolution of land attributes and correspondingly large areas of land; fine scale refers to a greater degree of spatial resolution of land attributes and smaller areas of land. The land attributes central to our discussion are existing and potential vegetative land cover and soil organic carbon (SOC) content.