Devil's Lake: Lake Superior Agate Rockhounding in Sauk County, Wisconsin

Quick details

Access

Permission required

County

Sauk County

State

Wisconsin

Nearest road

Devil's Doorway Trail

Coordinates

43.41357, -89.72002

Geology at Devil's Lake

This spot sits on ground mapped as Talus that formed within roughly the last 3 million years. Tough silica like agate and jasper typically survives weathering and collects as float in drainages and gravel.

Mapped unit

Talus

Age

3 Ma to present (Pleistocene)

Elevation

1,210 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 Devil's Lake

Best months: April to October. Typical highs run 81°F in midsummer and 26°F in midwinter, with winter lows near 8°F.

Climate normals: NOAA 1991-2020 monthlies, BARABOO WWTP station (3 mi away), adjusted for elevation.

Land & collecting status

Permission required before collecting

Requires landowner or agency permission before any collecting. Do not enter without explicit authorization.

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 Devil's Lake

Each chip opens all spots that produce that material; the encyclopedia link opens the full ID and field guide.

• Lake Superior AgateEncyclopedia →