Sand Creek: Montana Agate Rockhounding in Dawson County, Montana

Updated June 2026

Sand Creek is a mapped rockhounding spot in Dawson County, Montana. Reported finds include montana agate. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Dawson County
State: Montana
Coordinates: 46.92789, -104.81784

Geology at Sand Creek

This spot sits on Tongue River Member of Fort Union Formation, mapped as sandstone and shale that formed roughly 66 to 59 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: Tongue River Member of Fort Union Formation
Age: 66–59 Ma (Paleocene)
Rock types: sandstone and shale
Elevation: 2,200 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 Sand Creek

Best months: March to October. Typical highs run 87°F in midsummer and 29°F in midwinter, with winter lows near 9°F.

Climate normals: NOAA 1991-2020 monthlies, GLENDIVE station (13 mi away).

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 Sand Creek

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

Montana Agate Encyclopedia →

Nearby rockhounding spots

Other rockhounding spots within driving distance of Sand Creek.

Across the state line from Sand Creek

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

Sand Creek FAQ

Where is Sand Creek?+

Sand Creek is in Dawson County, Montana, at 46.92789, -104.81784.

What rocks and minerals can you find at Sand Creek?+

Sand Creek is reported to produce Montana Agate.

Is collecting allowed at Sand Creek?+

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 Sand Creek?+

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 Sand Creek?+

The most comfortable months at Sand Creek are March to October.

How do I get to Sand Creek?+

Open the directions link to navigate to 46.92789, -104.81784 in Google Maps. Some spots are remote, so check road conditions before driving out.

More rockhounding in Montana

See all 87 Montana spots →

Open Sand Creek on the map

Use the RockHoundR app for live land overlays, weather, geology, directions, and saved finds.