Steamboat Mountain: Agate & Chalcedony Rockhounding in Sweetwater County, Wyoming

Updated July 2026

Steamboat Mountain is a mapped rockhounding spot in Sweetwater County, Wyoming. Reported finds include agate, chalcedony, jasper, petrified wood. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Permission required
County: Sweetwater County
State: Wyoming
Coordinates: 41.96241, -108.96566

Geology at Steamboat Mountain

This spot sits on Alkalic extrusive and intrusive igneous rocks, mapped as alkalic volcanic and foidal syenitic that formed within roughly the last 3 million years. 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: Alkalic extrusive and intrusive igneous rocks
Age: 3 Ma to present (Pleistocene)
Rock types: alkalic volcanic and foidal syenitic
Elevation: 8,290 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 Steamboat Mountain

Best months: April to October. Typical highs run 79°F in midsummer and 24°F in midwinter, with winter lows near 8°F. At about 8,290 ft, snow can block access from late fall well into spring, so check conditions outside of summer.

Climate normals: NOAA 1991-2020 monthlies, ROCK SPRINGS AP station (26 mi away), adjusted for elevation.

Land & collecting status

Permission required before collecting

Requires landowner or agency permission before any collecting. Do not enter without explicit authorization.

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 Wyoming
Wyoming State Geological Survey
Fossil Butte National Monument
Community submissions reviewed against published agency rules

Found at Steamboat Mountain

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 Steamboat Mountain.

Across the state line from Steamboat Mountain

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

Steamboat Mountain FAQ

Where is Steamboat Mountain?+

Steamboat Mountain is in Sweetwater County, Wyoming, at 41.96241, -108.96566.

What rocks and minerals can you find at Steamboat Mountain?+

Steamboat Mountain is reported to produce Agate, Chalcedony, Jasper, Petrified Wood.

Is collecting allowed at Steamboat Mountain?+

Permission required before collecting. Requires landowner or agency permission before any collecting. Do not enter without explicit authorization. Always confirm current rules with the managing agency before a trip.

What tools should I bring to Steamboat Mountain?+

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 Steamboat Mountain?+

The most comfortable months at Steamboat Mountain are April to October. At about 8,290 ft, snow can block access from late fall well into spring, so check conditions outside of summer.

How do I get to Steamboat Mountain?+

Open the directions link to navigate to 41.96241, -108.96566 in Google Maps. Some spots are remote, so check road conditions before driving out.

More rockhounding in Wyoming

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Open Steamboat Mountain on the map

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