Tappen: Agate & Chalcedony Rockhounding in Kidder County, North Dakota

Updated June 2026

Tappen is a mapped rockhounding spot in Kidder County, North Dakota. Reported finds include agate, chalcedony, jasper, fossil. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Kidder County
State: North Dakota
Nearest road: Highway 10
Coordinates: 46.87959, -99.45691

Geology at Tappen

This spot sits on Pierre Formation, mapped as shale 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: Pierre Formation
Age: 100–66 Ma (Late Cretaceous)
Rock types: shale
Elevation: 1,750 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 Tappen

Best months: April to October. Typical highs run 81°F in midsummer and 19°F in midwinter, with winter lows near 1°F.

Climate normals: NOAA 1991-2020 monthlies, JAMESTOWN 38 WSW station (8 mi away), adjusted for elevation.

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 Tappen

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 Tappen.

Tappen FAQ

Where is Tappen?+

Tappen is in Kidder County, North Dakota, at 46.87959, -99.45691. Nearest road: Highway 10.

What rocks and minerals can you find at Tappen?+

Tappen is reported to produce Agate, Chalcedony, Jasper, Fossil.

Is collecting allowed at Tappen?+

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. Always confirm current rules with the managing agency before a trip.

What tools should I bring to Tappen?+

A rock hammer, a cold chisel, safety glasses, and newspaper or foam for wrapping finds cover most fossil ground. A trowel and a sieve help in soft exposures.

When is the best time to visit Tappen?+

The most comfortable months at Tappen are April to October.

How do I get to Tappen?+

Open the directions link to navigate to 46.87959, -99.45691 in Google Maps. The nearest road is Highway 10.

More rockhounding in North Dakota

See all 25 North Dakota spots →

Open Tappen on the map

Use the RockHoundR app for live land overlays, weather, geology, directions, and saved finds.