Ironside and Malheur Reservoir: Agate & Chalcedony Rockhounding in Malheur County, Oregon

Updated June 2026

Ironside and Malheur Reservoir is a mapped rockhounding spot in Malheur County, Oregon. Reported finds include agate, chalcedony, chert, jasper, petrified wood. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Malheur County
State: Oregon
Coordinates: 44.36240, -117.69807

Geology at Ironside and Malheur Reservoir

This spot sits on Powder River Volcanic Field; Little Catherine Creek member, mapped as basalt flows and olivine plagioclase phenocrysts that formed roughly 23 to 5 million years ago. Petrified wood typically comes from volcanic ash beds like the ones associated with this ground, where buried forests were slowly replaced by silica.

Mapped unit: Powder River Volcanic Field; Little Catherine Creek member
Age: 23–5 Ma (Miocene)
Rock types: basalt flows and olivine plagioclase phenocrysts
Elevation: 3,370 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.

Best time to visit Ironside and Malheur Reservoir

Best months: March to October. Typical highs run 90°F in midsummer and 32°F in midwinter, with winter lows near 17°F.

Climate normals: NOAA 1991-2020 monthlies, HUNTINGTON station (22 mi away), adjusted for elevation.

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.

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.

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.

State guidance last verified: April 1, 2026

BLM Oregon/Washington — Rockhounding & mineral material
Oregon Department of Geology and Mineral Industries (DOGAMI)
Oregon Parks and Recreation Department — beach collecting rules
Community submissions reviewed against published agency rules

Found at Ironside and Malheur Reservoir

Each chip 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 Ironside and Malheur Reservoir.

Across the state line from Ironside and Malheur Reservoir

Ironside and Malheur Reservoir is close enough to the Oregon border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.

Ironside and Malheur Reservoir FAQ

Where is Ironside and Malheur Reservoir?+

Ironside and Malheur Reservoir is in Malheur County, Oregon, at 44.36240, -117.69807.

What rocks and minerals can you find at Ironside and Malheur Reservoir?+

Ironside and Malheur Reservoir is reported to produce Agate, Chalcedony, Chert, Jasper, Petrified Wood.

Is collecting allowed at Ironside and Malheur Reservoir?+

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 Ironside and Malheur Reservoir?+

A rock hammer, sturdy gloves, and a padded bag cover petrified wood hunting. Most pieces are surface float, so walking slopes and washes beats digging.

When is the best time to visit Ironside and Malheur Reservoir?+

The most comfortable months at Ironside and Malheur Reservoir are March to October.

How do I get to Ironside and Malheur Reservoir?+

Open the directions link to navigate to 44.36240, -117.69807 in Google Maps. Some spots are remote, so check road conditions before driving out.

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Open Ironside and Malheur Reservoir on the map

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