Ilion Gorge: Travertine Rockhounding in Herkimer County, New York

Plan your visit

Generally open to casual rockhounding

County

Herkimer County

State

New York

Nearest road

Jerusalem Hill Road

Coordinates

42.96495, -75.11700

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: Park at the gated Jerusalem Hill Road on NY 51 about 5.8 miles south of Ilion and walk the closed paved road uphill roughly three quarters of a mile to the exposures. Loose scree comes off the banks and there is no cell signal in the gorge; the stream feeds a public water supply, so collect from fallen material along the road.

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 Ilion Gorge

Comfortable months (45 to 90°F highs)

Best months: April to November. Typical highs run 80°F in midsummer and 28°F in midwinter, with winter lows near 9°F.

Climate normals: NOAA 1991-2020 monthlies, LITTLE FALLS CITY RSCH station (14 mi away), adjusted for elevation.

Geology at Ilion Gorge

This spot sits on Vernon Shale, mapped as shale that formed roughly 425 to 420 million years ago. Sedimentary rock like this erodes unevenly, so the most productive collecting is typically along fresh cuts, badland slopes, and active drainages.

Mapped unit

Vernon Shale

Age

425–420 Ma (Ludlow to Pridoli)

Rock types

shale

Elevation

1,250 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.

• New York State Museum, Geological Survey
• NYS DEC land use rules
• Herkimer Diamond Mines
• Community submissions reviewed against published agency rules