Bismarck: Agate & Chalcedony Rockhounding in Burleigh County, North Dakota

Public accessBest spot4 mineralsBurleigh County, North DakotaUpdated July 2026

Minerals reported: 4
Elevation: 1,620 ft
Best months: April to October

Bismarck fronts the Missouri River, the one North Dakota waterway the courts have held navigable, meaning the state owns the bed below the ordinary high water mark. Its sand and gravel bars carry agate, chalcedony, jasper, and silicified wood eroded from upstream formations and glacial drift. Collecting is easiest from public river accesses, since Army Corps of Engineers parcels along the river are closed to removing material. Reported finds include agate, chalcedony, silicified wood, jasper. Below: coordinates, access notes, nearby spots, and trip-planning links.

Plan your visit

Generally open to casual rockhounding

County: Burleigh County
State: North Dakota
Nearest road: Gallatin Loop
Postcode: 58506
Coordinates: 46.75966, -100.83555

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Coordinates are approximate. Confirm the exact ground in the RockHoundR app, where land overlays show which agency manages the area.

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.

Access note: The Missouri River bed below the ordinary high water mark is state-owned sovereign land, but reach it from public accesses and avoid Army Corps of Engineers project land, where collecting is prohibited (36 CFR 327.14). Do not cross private banks without permission.

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.

Best time to visit Bismarck

24°J

28°F

41°M

56°A

69°M

78°J

85°J

84°A

74°S

58°O

41°N

28°D

Comfortable months (45 to 90°F highs)

Best months: April to October. Typical highs run 85°F in midsummer and 24°F in midwinter, with winter lows near 3°F.

Climate normals: NOAA 1991-2020 monthlies, BISMARCK station (4 mi away).

Geology at Bismarck

This spot sits on Hell Creek Formation, mapped as sandstone, siltstone, and claystone that formed roughly 100 to 66 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: Hell Creek Formation
Age: 100–66 Ma (Late Cretaceous)
Rock types: sandstone, siltstone, and claystone
Elevation: 1,620 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.

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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.

North Dakota Geological Survey
Dakota Prairie Grasslands
North Dakota Parks and Recreation rules
Community submissions reviewed against published agency rules

Found at Bismarck

Each name 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 Bismarck.

Teredo WoodMorton County, North Dakota · 4 mi awayTeredo Wood
MandanMorton County, North Dakota · 6 mi awayAgate, Chalcedony, Chert
Cannonball RiverSioux County, North Dakota · 28 mi awayAgate, Chalcedony, Silicified Wood
Crowley QuarryMercer County, North Dakota · 61 mi awayFlint
KilldeerDunn County, North Dakota · 64 mi awayKnife River Flint
TappenKidder County, North Dakota · 66 mi awayAgate, Chalcedony, Jasper
RichardtonStark County, North Dakota · 70 mi awayAgate, Chalcedony, Agatized Wood
Hettinger CountyHettinger County, North Dakota · 72 mi awayAgate, Chalcedony, Silicified Wood

Across the state line from Bismarck

Bismarck 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 EagleCorson County, South Dakota · 75 mi awayPetrified Wood, Opal
Mound CityCampbell County, South Dakota · 77 mi awayPetrified Wood, Opal

Bismarck FAQ

Where is Bismarck?+

Bismarck is in Burleigh County, North Dakota, at 46.75966, -100.83555. Nearest road: Gallatin Loop.

What rocks and minerals can you find at Bismarck?+

Bismarck is reported to produce Agate, Chalcedony, Silicified Wood, Jasper.

Is collecting allowed at Bismarck?+

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 Bismarck?+

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 Bismarck?+

The most comfortable months at Bismarck are April to October.

How do I get to Bismarck?+

Open the directions link to navigate to 46.75966, -100.83555 in Google Maps. The nearest road is Gallatin Loop.

More rockhounding in North Dakota

See all 25 North Dakota spots →

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