This dataset represents sedimentary basins associated with the U.S. Energy Information Administration (EIA) shale plays as of May 6, 2011. A play is a set of known or postulated oil and gas accumulations sharing similar geologic, geographic, and temporal properties, such as source rock, migration pathway, timing, trapping mechanism, and hydrocarbon type. A play is often used to refer to a natural gas accumulation; in this case a natural gas shale play. Shale gas is produced from wells that are open to shale formations. Shale is a fine-grained, sedimentary rock composed of mud from flakes of clay minerals and tiny fragments (silt-sized particles) of other materials.

Land containing shale are susceptible to hyrdaulic fracturing, or fracking, which is the fracturing of rock at depth with fluid pressure. Hydraulic fracturing at depth may be accomplished by pumping water into a well at very high pressures. Under natural conditions, vapor pressure may rise high enough to cause fracturing in a process known as hydrothermal brecciation.

Sedimentary basin which do not have shale plays as of publication date are not included in this file. Sources for the basins are mostly from the US Geological Survey and state agencies such as the WY Geological Survey.