Prairie Research Institute

Illinois State Geological Survey

Geological Records

The Illinois State Geological Survey (ISGS) is the official state repository for drilling records. ISGS holds records for more than 500,000 oil and gas wells, water wells, engineering borings, and miscellaneous test holes drilled in Illinois. This information is useful for environmental assessment, mineral resource evaluation, and groundwater resource evaluation and protection.

Online Map of Illinois Oil and Gas Resources

ISGS provides an interactive online map of Illinois’ oil and gas resources; this map draws on thousands of oil and gas well records held by ISGS. In addition, users can view data layers such as producing horizons, samples, core analysis data, structure contours, waterflood areas, and oil fields. Through these layers the ILOIL application also provides access to other resources, including well summary sheets, logs, scout check tickets, core analysis reports, and oil field statistics.

Launch ILOIL

Online Map of Illinois Water Wells

ISGS holds records for thousands of water wells, with some records dating back as far as the late 1800s. Water and related well data can be accessed for private water wells, engineering borings, and stratigraphic borings.  Many of these records have been digitized and data can be searched using the ILWATER interactive online map.


Custom Data Queries

For users who need to access data for a broad area, particularly those who would like to load data directly into their mapping or modeling software, ISGS staff can provide data packages based on customized queries of the well database. The data will be packaged as a text file delimited with “$” and will be delivered by email or FTP server.

After a $20 set-up fee, the cost per well header is $0.09 and $0.09 for additional well information, if requested.  When purchasing an entire county, there is a 10% discount.

For data purchases for the entire state, there is a flat fee:

  • $15,000 for oil and gas well header data, plus $5,000 for the additional data, if requested. 
  • $20,000 for water well headers, plus $12,000 for the additional data, if requested.

To request a custom data package, email or call 217-333-5109.

Accessing Drilling Records

Paper records can be accessed at the Illinois State Geological Survey headquarters in Champaign. Records are filed by location (county, section, township, and range). Please have this information ready when requesting information. Some sources for legal descriptions are tax records, property titles and mortgage records, and plat books.

Copies and scans of ISGS paper well records are available; nominal fees are charged for copying, scanning, and shipping.

Hours: Monday – Friday, 8 a.m.- 4:30 p.m. Closed on all University of Illinois holidays.
Phone: 217-333-5109
Fax: 217-244-4544


Location: Room 239, Natural Resources Building, Champaign, IL

Mailing address:
Geological Records Unit
Illinois State Geological Survey
615 E. Peabody Dr., Room 239
M/C 650
Champaign, IL 61820

Geological Record Collections at ISGS

Drilling Records

  • Oil, gas, and Class II injection well records
  • Water well records
  • Coal test permits, plugging affidavits and records
  • Out-of-state records used in ISGS projects
  • Engineering reports
  • Highway and bridge borings
  • Sample studies
  • Structure and stratigraphic tests
  • Historical well records of many types, including skeleton logs

Additional Resources

  • Pipeline production books
  • Historical and current collections of scout tickets
  • Historical and current plat books
  • Oil and gas development maps
  • Office of Mines and Minerals well files


ISGS maintains paper copies of individual well files. All documents for each drill hole are filed together in a folder and organized by location, including items such as:

  • geophysical logs
  • drillers log
  • drilling time log
  • drill stem test report
  • core analysis report
  • commercial scout tickets
  • index numbers for samples and cores housed in the Samples Library
  • permit
  • casing report
  • well drilling report
  • well completion report
  • plugging affidavit
  • summary sheet – generated when all the documents for the well have been received

Water Well Records

Most water wells have relatively few documents and rarely have individual folders. Water well construction and permit information is included in the water well summary sheets in the ISGS log books. The water well source documents (the applications, permits, and construction reports generated through September 1997) are maintained by ISGS. The Illinois State Water Survey maintains the later source documents.

Well Log Books

The well log books contain summary sheets for all types of drill holes. The books are the sole source of many records and also serve as an index to ISGS file folders. Currently, the collection contains 1,356 log books with approximately 680,000 pages on over 500,000 drill holes. These are arranged by county, then by township, range, and section. The books include

  • oil well summary sheet
  • report of gas flow measurement
  • water well summary sheet
  • index to cores in the ISGS Samples Library
  • bridge boring report
  • engineering report index
  • skeleton logs – pre-1920 oil well records, mainly in Crawford, Lawrence, Clark and Cumberland counties.

Wells Database

The well records database includes most of the basic identification information from our log books and files. It also includes much of the geologic formation and well construction/completion information. The database provides very versatile search capabilities. We are working toward making the database our most complete access tool. However, to be assured of a comprehensive search of our collections now, use all three access points: folders, well log books, and database.