Where to Find Geodes in Illinois: 11 Mapped Sites
Illinois has 11 documented sites where geodes have been reported, and the best-known are Crystal Glen Creek, Spillman Creek, and Hamilton Quarry. Every site is mapped below with GPS coordinates and links to a full report of access and what's been found there. 11 of the 11 sites are on public-access land.
Last updated: — data compiled by the Rockhounding.org Research Team · methodology
Geodes Map: Illinois
All 11 geodes sites in Illinois. Click a pin for the full site report.
Where Geodes Are Found in Illinois
Geodes form in gas pockets in basalt and in dissolution cavities in limestone, then weather out into creeks and slopes. Look in streambeds and roadcuts through limestone country.
The richest reported sites in Illinois: Crystal Glen Creek, Spillman Creek, Hamilton Quarry, Dallas City, Hamilton.
Of the 11 sites, 11 are public access. Check each site report for current land status before you go.
All Geodes Sites in Illinois
- Crystal Glen Creek — Public Access
- Spillman Creek — Public Access
- Hamilton Quarry — Public Access
- Dallas City — Public Access
- Hamilton — Public Access
- Mississippi River (near Hamilton) — Public Access
- McKee Creek — Public Access
- Niota — Public Access
- Hamilton (west) — Public Access
- Nauvoo — Public Access
- Tyson Creek — Public Access
How to Identify Geodes
A geode is a round or oblong nodule with a bumpy, cauliflower-textured shell that feels noticeably light for its size — the hollow interior gives it away. Some rattle when shaken. Crack one open and the cavity is lined with inward-pointing quartz or calcite crystals; a solid, heavy nodule is more likely a concretion.
Not sure what you found? Try our identification guide →Frequently Asked Questions
Where can I find geodes in Illinois?
Illinois has 11 mapped sites where geodes have been reported. The best-known are Crystal Glen Creek, Spillman Creek, and Hamilton Quarry. Each listing on the map above includes GPS coordinates, access type, and what has been found there.
How many geodes sites are mapped in Illinois?
We have 11 documented geodes sites in Illinois, compiled from community submissions and published locality records and reviewed by the Rockhounding.org Research Team.
Is it legal to collect geodes in Illinois?
Casual collecting is generally allowed on BLM and National Forest land for personal, non-commercial use — the standard BLM limit is 25 lbs per day plus one specimen. National parks, monuments, and many state parks prohibit collecting, and private land always requires the owner's permission. Check the site report for each location and verify current land status before you dig.
How do I identify geode?
A geode is a round or oblong nodule with a bumpy, cauliflower-textured shell that feels noticeably light for its size — the hollow interior gives it away. Some rattle when shaken. Crack one open and the cavity is lined with inward-pointing quartz or calcite crystals; a solid, heavy nodule is more likely a concretion.
What should I bring to collect geodes?
The basics: a rock hammer, safety glasses, gloves, a bucket or padded bag for specimens, and a GPS app with the coordinates from this page. Add a spray bottle — wetting a stone makes color and banding far easier to judge in the field.
⚠️ Always verify current regulations, weather conditions, and access requirements before visiting any location. Information provided is based on community submissions and may not be current or accurate.
More to Find in Illinois
Data: community submissions — reviewed and approved by the Rockhounding.org Research Team. Always verify current land status, regulations, and access before visiting any site.