Souris River: Quartz & Agate Rockhounding in McHenry County, North Dakota
Updated July 2026
The Souris, or Mouse, River loops through the drift prairie of north-central North Dakota, and its glacial gravels carry quartz, agate, chalcedony, and jasper eroded from Canadian bedrock and dropped by the ice sheets. Gravel bars and cutbanks in McHenry County are the collecting ground. The river is non-navigable, so legal access runs through public river accesses and permission on private land. Reported finds include quartz, agate, chalcedony, jasper, fossil. Below: coordinates, access notes, nearby spots, and trip-planning links.
Souris River photos
Public image records connected to this spot or its reported material.
Map showing Souris River in McHenry County, North Dakota
Quick details
- Access
- Public area
- County
- McHenry County
- State
- North Dakota
- Nearest road
- River Road North
- Coordinates
- 48.11499, -100.80194
Geology at Souris River
This spot sits on Hell Creek Formation, mapped as sandstone, siltstone, and claystone that formed roughly 100 to 66 million years ago. Sedimentary layers like these are where fossils are typically preserved, and fresh exposures after rain or in active cuts tend to produce best.
- Mapped unit
- Hell Creek Formation
- Age
- 100–66 Ma (Late Cretaceous)
- Rock types
- sandstone, siltstone, and claystone
- Elevation
- 1,480 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 Souris River
Best months: April to October. Typical highs run 80°F in midsummer and 20°F in midwinter, with winter lows near -3°F.
Climate normals: NOAA 1991-2020 monthlies, VELVA station (7 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 Souris 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 Souris River.
- Turtle MountainRolette County, North Dakota · 63 mi awayQuartz, Agate, Chalcedony
- Crowley QuarryMercer County, North Dakota · 71 mi awayFlint
- StanleyMountrail County, North Dakota · 80 mi awayGlauberite, Halite, Thenardite
- KilldeerTop pick in North DakotaDunn County, North Dakota · 88 mi awayKnife River Flint
- Sheyenne RiverEddy County, North Dakota · 89 mi awayQuartz, Petrified Wood, Fossil
- MandanTop pick in North DakotaMorton County, North Dakota · 90 mi awayAgate, Chalcedony, Chert
- Teredo WoodMorton County, North Dakota · 92 mi awayTeredo Wood
- BismarckTop pick in North DakotaBurleigh County, North Dakota · 94 mi awayAgate, Chalcedony, Silicified Wood
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More rockhounding in North Dakota
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