Knife River beaches: Lake Superior Agate Rockhounding in Lake County, Minnesota
Updated July 2026
The cobble beaches at Knife River are one of the North Shore's most reliable places to hunt Lake Superior agate, Minnesota's state gemstone, formed roughly a billion years ago in the gas vesicles of Keweenawan basalt along the Midcontinent Rift. Storms sort the shoreline gravel and expose fresh material, and both the lakeshore and the lower Knife River banks produce banded agate. The Knife River Marina beach offers rare, dedicated public parking and access directly on Lake Superior. Reported finds include lake superior agate. Below: coordinates, access notes, nearby spots, and trip-planning links.
Knife River beaches photos
Public image records connected to this spot or its reported material.
Map showing Knife River beaches in Lake County, Minnesota
Quick details
- Access
- Public area
- County
- Lake County
- State
- Minnesota
- Nearest road
- Sciff Landing Road
- Postcode
- 55609
- Coordinates
- 46.95035, -91.77834
Geology at Knife River beaches
This spot sits on Basalt and basaltic andesite, mapped as basalt and basaltic andesite that formed roughly 1200 to 1000 million years ago. Volcanic ground like this is where agate, jasper, and other chalcedony typically form, filling old gas pockets and fracture seams in the flow rock.
- Mapped unit
- Basalt and basaltic andesite
- Age
- 1200–1000 Ma (Mesoproterozoic)
- Rock types
- basalt and basaltic andesite
- Elevation
- 590 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 Knife River beaches
Best months: April to October. Typical highs run 75°F in midsummer and 24°F in midwinter, with winter lows near 8°F.
Climate normals: NOAA 1991-2020 monthlies, TWO HARBORS 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 Knife River beaches
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 Knife River beaches.
- French RiverSaint Louis County, Minnesota · 7 mi awayLake Superior Agate
- Kelsey BeachTop pick in MinnesotaLake County, Minnesota · 10 mi awayLake Superior Agate
- Gull RockLake County, Minnesota · 27 mi awayLake Superior Agate
- Beaver BayTop pick in MinnesotaLake County, Minnesota · 31 mi awayLake Superior Agate, Thomsonite
- Cloquet (area 2)Carlton County, Minnesota · 36 mi awayLake Superior Agate, Garnet, Greenalite
- CarltonCarlton County, Minnesota · 36 mi awayLake Superior Agate, Garnet, Greenalite
- CloquetTop pick in MinnesotaCarlton County, Minnesota · 37 mi awayLake Superior Agate, Garnet, Greenalite
- Little Marais RiverLake County, Minnesota · 45 mi awayThomsonite, Zeolite
Across the state line from Knife River beaches
Knife River beaches is close enough to the Minnesota border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.
- Wisconsin PointTop pick in WisconsinDouglas County, Wisconsin · 20 mi awayLake Superior Agate, Jasper, Copper
- AnniconDouglas County, Wisconsin · 31 mi awayCopper
- Bayfield CountyTop pick in WisconsinBayfield County, Wisconsin · 31 mi awayAgate, Jasper
- Ounce CreekDouglas County, Wisconsin · 52 mi awayAgate, Azurite, Bornite
- Big Bay Town ParkTop pick in WisconsinAshland County, Wisconsin · 55 mi awayLake Superior Agate, Jasper, Thomsonite
- General AreaAshland County, Wisconsin · 65 mi awayCopper
Knife River beaches FAQ
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More rockhounding in Minnesota
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