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Cordova: Agate Rockhounding in Rock Island County, Illinois

Public accessBest spot1 mineralRock Island County, IllinoisUpdated July 2026
Mineral reported
1
Elevation
620 ft
Best months
March to November

The Mississippi River gravel bars at Cordova are among Illinois's most reliable spots for Lake Superior agate, carried south by glacial meltwater from the agate source region in Minnesota and Wisconsin. The red-and-orange fortification banding, colored by iron oxide, distinguishes these agates in the mixed river gravel, which also holds jasper and quartz. Each flood cycle re-sorts the bars and exposes new material. Reported finds include agate. Below: coordinates, access notes, nearby spots, and trip-planning links.

Plan your visit

Generally open to casual rockhounding

Nearest road
River Road North
Postcode
61242
Get directionsView on Google Maps

Coordinates are approximate. Confirm the exact ground in the RockHoundR app, where land overlays show which agency manages the area.

Land & collecting status

Generally open to casual rockhounding

Most public-tagged spots sit on BLM, U.S. Forest Service, or other federal land where reasonable hand collecting of common rocks and minerals is allowed. Confirm posted rules and active mining claims before you dig.

Access note: Search the exposed gravel bars from public river accesses along the Mississippi, where the riverbed below the ordinary high-water mark is state-owned public-trust land. Surface-collect only and avoid crossing private riverfront property. Rock Island County, northwestern Illinois. Water levels are lowest in late summer and fall.

Public-land rules vary by agency, season, and field office. The RockHoundR app pulls live BLM, USFS, NPS, and tribal overlays so you can see exactly which agency manages the ground at this spot.

Best time to visit Cordova

Comfortable months (45 to 90°F highs)

Best months: March to November. Typical highs run 84°F in midsummer and 29°F in midwinter, with winter lows near 14°F.

Climate normals: NOAA 1991-2020 monthlies, CLINTON #1 station (6 mi away).

Geology at Cordova

This spot sits on ground mapped as dolostone and limestone that formed roughly 445 to 420 million years ago. Chert and agate nodules typically form inside carbonate rock like this and weather out as tough, waxy lumps in soils and creek beds.

Age
445–420 Ma (Llandovery to Pridoli)
Rock types
dolostone and limestone
Elevation
620 ft

Geologic mapping via Macrostrat and the underlying state geological survey maps (CC BY 4.0). Bedrock at the surface can vary within a mapped unit.

Today's weather

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Sources & verification

Spot details combine the public RockHoundR location dataset, normalized mineral labels, agency land-status checks in the app, and community submissions. Coordinates are approximate until verified in the field.

Found at Cordova

Each name opens all spots that produce that material; the encyclopedia link opens the full ID and field guide.

Nearby rockhounding spots

Other rockhounding spots within driving distance of Cordova.

Across the state line from Cordova

Cordova is close enough to the Illinois border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.

Cordova FAQ

Where is Cordova?+
Cordova is in Rock Island County, Illinois, at 41.71600, -90.31123. Nearest road: River Road North.
What rocks and minerals can you find at Cordova?+
Cordova is reported to produce Agate.
Is collecting allowed at Cordova?+
Generally open to casual rockhounding. Most public-tagged spots sit on BLM, U.S. Forest Service, or other federal land where reasonable hand collecting of common rocks and minerals is allowed. Confirm posted rules and active mining claims before you dig. Always confirm current rules with the managing agency before a trip.
What tools should I bring to Cordova?+
Most agate and jasper is surface float: bring a spray bottle, a pick or small shovel, and a sturdy bag. Wet stones show their banding and translucence.
When is the best time to visit Cordova?+
The most comfortable months at Cordova are March to November.
How do I get to Cordova?+
Open the directions link to navigate to 41.71600, -90.31123 in Google Maps. The nearest road is River Road North.

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