Yellowstone River (Billings area): Montana Agate & Chalcedony Rockhounding in Yellowstone County, Montana
- Minerals reported
- 4
- Elevation
- 3,000 ft
- Best months
- March to November
The Billings reach of the Yellowstone River is a benchmark Montana agate setting, where river gravels carry chalcedony, jasper, chert, and dendritic moss agate. Mindat records agate from Yellowstone County, and regional visitor and BLM guidance both point collectors toward public-land surface collecting rather than quarry or fee-pit material. Reported finds include montana agate, chalcedony, chert, jasper. Below: coordinates, access notes, nearby spots, and trip-planning links.
Plan your visit
Generally open to casual rockhounding
- County
- Yellowstone County
- State
- Montana
- Nearest road
- Highway 312
- Postcode
- 59037
- Coordinates
- 45.90541, -108.31735
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: Use public river access such as legal fishing-access or BLM-managed areas; do not collect in protected sites, private parcels, or closed areas.
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 Yellowstone River (Billings area)
Comfortable months (45 to 90°F highs)
Best months: March to November. Typical highs run 87°F in midsummer and 35°F in midwinter, with winter lows near 12°F.
Climate normals: NOAA 1991-2020 monthlies, HUNTLEY EXP STN station (4 mi away).
Geology at Yellowstone River (Billings area)
This spot sits on Alluvium, mapped as gravel, sand, and silt that formed within roughly the last 2 million years. Gravels like these concentrate whatever survives the river: agate, jasper, and other tough silica typically show up as rounded, waxy stones.
- Mapped unit
- Alluvium
- Age
- 2 Ma to present (Pleistocene to Holocene)
- Rock types
- gravel, sand, and silt
- Elevation
- 3,000 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.
Today's weather
Is today a good day to go?
The app shows live weather, recent rain, and a daily rockhounding score for Yellowstone River (Billings area).
Get the appSources & 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:
- 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 Yellowstone River (Billings area)
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 Yellowstone River (Billings area).
- Yellowstone River - Blue Creek AccessYellowstone County, Montana · 16 mi awayMontana Moss Agate, Petrified Wood, Jasper
- Yellowstone River - Bundy Bridge Fishing AccessYellowstone County, Montana · 16 mi awayMontana Moss Agate, Petrified Wood, Jasper
- Yellowstone River - Laurel Sportsman AccessYellowstone County, Montana · 32 mi awayMontana Moss Agate, Petrified Wood, Jasper
- Big Horn CanyonBig Horn County, Montana · 44 mi awayAgate, Chalcedony, Jasper
- Pryor MountainsBig Horn County, Montana · 46 mi awayFossil, Agate, Chalcedony
- FrombergCarbon County, Montana · 46 mi awayCoal, Pyrite
- Yellowstone River - Holmgren Fishing AccessStillwater County, Montana · 53 mi awayMontana Moss Agate, Petrified Wood, Jasper
- Yellowstone River - Myers Bridge AccessTreasure County, Montana · 53 mi awayMontana Moss Agate, Petrified Wood, Jasper
Across the state line from Yellowstone River (Billings area)
Yellowstone River (Billings area) 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.
- Big Horn RiverBig Horn County, Wyoming · 65 mi awayDry Head Agate
- LovellBig Horn County, Wyoming · 78 mi awayFossil, Ammonite, Dinosaur Bone
- LovellBig Horn County, Wyoming · 79 mi awayGypsum, Fossil
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