Hysham: Moss Agate Rockhounding in Treasure County, Montana

Updated June 2026

Hysham is a mapped rockhounding spot in Treasure County, Montana. Reported finds include moss agate. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Treasure County
State: Montana
Coordinates: 46.17737, -107.17897

Geology at Hysham

This spot sits on Lance Formation, mapped as sandstone that formed roughly 84 to 66 million years ago. Tough silica like agate, jasper, and chert typically weathers out of beds like these and collects as float in drainages and on deflation surfaces.

Mapped unit: Lance Formation
Age: 84–66 Ma (Late Cretaceous)
Rock types: sandstone
Elevation: 2,990 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 Hysham

Best months: March to November. Typical highs run 86°F in midsummer and 34°F in midwinter, with winter lows near 11°F.

Climate normals: NOAA 1991-2020 monthlies, HYSHAM station (8 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 Montana — Recreational mineral collecting
Montana Bureau of Mines and Geology
Gem Mountain Sapphire Mine (fee-dig operator)
Community submissions reviewed against published agency rules

Found at Hysham

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

Moss Agate Encyclopedia →

Nearby rockhounding spots

Other rockhounding spots within driving distance of Hysham.

Hysham FAQ

Where is Hysham?+

Hysham is in Treasure County, Montana, at 46.17737, -107.17897.

What rocks and minerals can you find at Hysham?+

Hysham is reported to produce Moss Agate.

Is collecting allowed at Hysham?+

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 Hysham?+

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 Hysham?+

The most comfortable months at Hysham are March to November.

How do I get to Hysham?+

Open the directions link to navigate to 46.17737, -107.17897 in Google Maps. Some spots are remote, so check road conditions before driving out.

More rockhounding in Montana

See all 87 Montana spots →

Open Hysham on the map

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