Biwabik: Lake Superior Agate & Iron Rockhounding in Saint Louis County, Minnesota

Plan your visit

Generally open to casual rockhounding

County

Saint Louis County

State

Minnesota

Nearest road

Old Highway 135

Postcode

55708

Coordinates

47.52938, -92.36620

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.

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 Biwabik

Comfortable months (45 to 90°F highs)

Best months: April to October. Typical highs run 77°F in midsummer and 17°F in midwinter, with winter lows near -1°F.

Climate normals: NOAA 1991-2020 monthlies, EVELETH WWTP station (9 mi away).

Geology at Biwabik

This spot sits on Gunflint (~1,878 Ma), Biwabik, and Emily Iron Formations, mapped as banded iron formation and sedimentary breccia that formed roughly 2050 to 1800 million years ago. Tough silica like agate, jasper, and chert typically weathers out of beds like these and collects as float in drainages and on deflation surfaces.

Mapped unit

Gunflint (~1,878 Ma), Biwabik, and Emily Iron Formations

Age

2050–1800 Ma (Paleoproterozoic)

Rock types

banded iron formation and sedimentary breccia

Elevation

1,410 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.

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.

• Minnesota Geological Survey
• Minnesota DNR state land rules
• Superior National Forest
• Community submissions reviewed against published agency rules