Illinois Boring Logs & Geotechnical Data
22,054 public boring logs in Illinois; 20,058 with digitized SPT, soil or CPT data; 1,996 scanned log PDFs. Sources include Chicago DOT (CDOT), Illinois State Geological Survey (ISGS), Caltrans, plus public reports found by web crawl. Free to search on the map, download or query by API.
Where the data comes from
- Chicago DOT (CDOT)8,293
- Public reports collected by web crawl7,334
- Illinois State Geological Survey (ISGS)6,387
- Caltrans15
- Wisconsin DOT (WisDOT)14
- USGS CPT program5
- Kentucky Transportation Cabinet (KYTC)3
- Missouri DOT (MoDOT)3
Web-crawled reports in Illinois were published on, among others: apps.dot.illinois.gov, apps1.dot.illinois.gov, semspub.epa.gov, chicago.gov, pcb.illinois.gov, cdb.illinois.gov.
Counties with the most boring logs
| County | Boring logs | |
|---|---|---|
| Cook | 10,425 | view on map |
| Will | 1,238 | view on map |
| DuPage | 526 | view on map |
| Lake | 460 | view on map |
| Kane | 386 | view on map |
| Rock Island | 337 | view on map |
| Madison | 278 | view on map |
| Champaign | 249 | view on map |
| St. Clair | 239 | view on map |
| LaSalle | 232 | view on map |
| McHenry | 229 | view on map |
| Kankakee | 228 | view on map |
What's in a boring log from Illinois
The 20,058 digitized borings carry the data engineers actually use: SPT blow counts (N-values) by depth, soil and rock descriptions, groundwater observations and, where the source ran cone penetration tests, CPT tip resistance and sleeve friction. A further 1,996 logs are scanned PDF reports — the original agency drawings — which you can open and download from the map. Holes are typically about 62 ft (19 m) deep; one in twenty goes past 582 ft (177 m). Not sure what a boring log looks like? See annotated example boring logs.
How to get this data
- Map — pan to a site, click a boring, and view the log, the original PDF, or an ML soil-profile prediction. No account needed.
- Downloads — every boring exports as PDF, DIGGS XML or AGS4; draw a polygon on the map for a multi-boring export or a site report.
- API — query borings by coordinates or bounding box, pull SPT/CPT/lab records, and generate site reports programmatically.
- Contribute — have Illinois boring logs that are not here yet? We take PDFs, DIGGS, AGS and spreadsheets.
This data was collected from public agencies and is republished as-is. It is a planning tool, not a substitute for a site investigation; see the terms and disclaimer. Counts refreshed 2 November 2026.
Other places
Washington (186,877)Florida (171,716)Ohio (80,944)California (75,283)Oregon (71,862)North Carolina (70,533) all regions →