Evaporite sinkholes are locally common in Eagle and Garfield Counties in northwestern Colorado. Until the past several decades the region was sparsely inhabited, and sinkholes presented little risk to works of man. However, since the late 1960s the region has experienced a marked increase in development. To date, sinkhole-related structural problems have been rare, but the potential for problems increases with increased development. Large amounts of evaporite were deposited in the Central Colorado trough during the Pennsylvanian Period. The evaporite is the predominant constituent of the Eagle Valley Evaporite and is present to a lesser extent in the Eagle Valley Formation. Three sinkhole forms are recognized: Type A deep rubble pipe sinkholes that disturb the entire soil profile above the evaporite, Type B shallow fissure piping sinkholes that disturb only the upper tier of fine-grained soil, and Type C cavity roof collapse sinkholes related to direct solution cavity collapse in the evaporite. The sinkholes appear to evolve through five development stages: Stage I pre-surface collapse, Stage II initial surface collapse, Stage III rim stabilization, Stage IV soil infilling, and Stage V concealment. Sinkhole formation is an active geologic process as indicated by historic surface collapse. Because of the complex nature of the evaporite sinkholes, it will not be possible to avoid all risks to works of man, but the risks can be reduced by facility-specific geotechnical studies and mitigation designs.