Brines
No salt is now produced in Illinois, but at one time the state was a major salt producer. Salt works were in operation near Equality, Central City, Murphysboro, St. John, Danville, and possibly other places. The salt was obtained by evaporating salt water (brine) that came from natural springs or from wells. The Equality area was a particularly important producer of salt in the 1800’s. Discovery elsewhere in the Middle West of deposits of rock salt and brines that contained more salt than those of Illinois is said to have been responsible for the discontinuance of salt making in the state.
No salt beds crop out in Illinois, nor are any known to have been encountered in the many wells that have been drilled for coal, oil, or water. However, most oil well drilling encounters brines containing various amounts and kinds of salts, including the common table salt, sodium chloride.
For reasons relating to the production of oil, Survey geologists and chemists have collected and analyzed many samples of Illinois oil field brines, and data are therefore available on their salt content. No commercial use is being made of the brines as sources of salt.