Best spot

Little Missouri River: Montana Moss Agate & Jasper Rockhounding in McKenzie County, North Dakota

Updated July 2026

The Little Missouri River drains the heart of the North Dakota badlands, and its gravel bars concentrate Montana moss agate, agatized wood, and jasper eroded from the Sentinel Butte and Bullion Creek formations and carried down from Montana. Where the river and its benches cross the Little Missouri National Grassland, surface collecting of these materials is legal for personal use. The river is non-navigable, so its bed is privately owned in many reaches, and grassland tracts give the easiest legal access. Reported finds include montana moss agate, jasper, agatized wood. Below: coordinates, access notes, nearby spots, and trip-planning links.

Little Missouri River photos

Public image records connected to this spot or its reported material.

1 photo

Little Missouri River winding through the badlands of the Little Missouri National Grassland, North Dakota

Quick details

Access: Public area
County: McKenzie County
State: North Dakota
Coordinates: 47.52395, -103.45211

Geology at Little Missouri River

This spot sits on Bullion Creek Formation, mapped as claystone and siltstone that formed roughly 66 to 56 million years ago. Sedimentary beds like these are the typical host for petrified and silicified wood, which weathers out as durable float on slopes and in washes.

Mapped unit: Bullion Creek Formation
Age: 66–56 Ma (Paleocene)
Rock types: claystone and siltstone
Elevation: 1,980 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 Little Missouri River

Best months: April to October. Typical highs run 85°F in midsummer and 24°F in midwinter, with winter lows near 2°F.

Climate normals: NOAA 1991-2020 monthlies, WATFORD CITY 14S station (10 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.

Sources: RockHoundR public spot dataset, app land overlays, and local agency review before each trip.

Found at Little Missouri River

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 Little Missouri River.

Across the state line from Little Missouri River

Little Missouri River is close enough to the North Dakota border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.

Little Missouri River FAQ

Where is Little Missouri River?+

Little Missouri River is in McKenzie County, North Dakota, at 47.52395, -103.45211.

What rocks and minerals can you find at Little Missouri River?+

Little Missouri River is reported to produce Montana Moss Agate, Jasper, Agatized Wood.

Is collecting allowed at Little Missouri River?+

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 Little Missouri River?+

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 Little Missouri River?+

The most comfortable months at Little Missouri River are April to October.

How do I get to Little Missouri River?+

Open the directions link to navigate to 47.52395, -103.45211 in Google Maps. Some spots are remote, so check road conditions before driving out.

More rockhounding in North Dakota

See all 20 North Dakota spots →

Open Little Missouri River on the map

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