In the past a series of reports on coal resources of selected counties in Indiana were published as part of the Special Report series of the Indiana Geological Survey. These reports included maps showing extent of the Colchester Coal Member (Linton Formation, Pennsylvanian). The extent maps were based on coal-test records, mine-map notations, and interpretations of geophysical logs that are included in the files of the Indiana Geological Survey. Since 1980, staff members of the Indiana Geological Survey (IGS) have also collected and entered coal resource information into the NCRDS Database as a cooperative project with the U.S. Geological Survey (USGS). The purpose of NCRDS Database is to provide a means of rapid retrieval of point-source coal resource information, including coal location, extent, and other parameters. Based on all available NCRDS data and data provided by Phil Ames from the Peabody Coal Company as of August 2014, a new map of Colchester Coal Member extent was created. It is the most current extent map of the Colchester Coal Member. Because additional data on coal extent are obtained by the Indiana Geological Survey on an annual basis, interested users may wish to contact the IGS for information on these more up-to-date sources.