Rockhounding in Hillsborough County, NH: 17 USGS Mineral Sites (2026)

Check access before you go. Most sites listed here are old mines, quarries or prospects, and many are on private land or active mining claims. Get the landowner's permission, check the rules of the agency that manages any public land, and never enter mine workings. Locations are approximate.

Sketch map

Past ProducerProducerProspectOccurrenceStatus unknown

14 paw pins; nearby sites are grouped into one pin. Hover or tap a pin for the site name. County outline: US Census Bureau cartographic boundary file (2023). Locations approximate.

Field cards: what kind of sites?

Prospect

Explored or test-dug, with no recorded production.

Past Producer

Produced ore or material at some point in the past.

Producer

Was producing when the record was made.

Status terms come from USGS MRDS records.

Minerals recorded here

Granite 2

Commodities

Silica 10Granite 4Talc-Soapstone 2Titanium 1

Sites

Site	Commodity	Minerals recorded	Status	Approx. location
Maine New Hampshire Granite Corp	Granite	Granite	Past Producer	42.732, -71.777
Barretto Granite Corp	Granite	Granite	Past Producer	42.817, -71.737
Kendall Ledge Quartz	Silica	—	Prospect	42.836, -71.838
Stinson Quartz Prospect	Silica	—	Prospect	43.042, -71.599
South Lyndeborough Silica Mine	Silica	—	Past Producer	42.897, -71.759
Mason Quarry	Granite	—	Producer	42.732, -71.777
Riverdale Quartz	Silica	—	Prospect	43.032, -71.639
Merrimack Foundry Sand Prospect	Silica	—	Prospect	42.877, -71.487
Kitledge Quarry	Granite	—	Producer	42.817, -71.737
South Lyndeborough Quartz	Silica	—	Prospect	42.896, -71.766
Harry Brook Quartz Prospect	Silica	—	Prospect	43.051, -71.576
Francestown Soapstone Co. Quarry	Talc-Soapstone	—	Past Producer	43.006, -71.785
Ledge Hill Quartz	Silica	—	Prospect	42.952, -71.583
Merrimack Mine	Titanium	—	Past Producer	42.854, -71.537
Mitchell Hill Quartz	Silica	—	Prospect	42.793, -71.737
Purgatory Quartz Prospect	Silica	—	Prospect	43.064, -71.540
Hogdon Quarry	Talc-Soapstone	—	Past Producer	43.060, -71.766

Nearby counties

Rockingham County · Cheshire County · Merrimack County · Sullivan County · Strafford County

New Hampshire mineral guides

Back to all New Hampshire counties.

How we built this page: we counted named sites in the USGS Mineral Resources Data System (MRDS) for this area, left out sand, gravel, crushed stone, clay pits and unnamed sites, grouped them by Census county, and linked every site to its USGS record. We did not visit these sites, and MRDS does not tell you who owns the land or whether collecting is allowed.

Source: USGS Mineral Resources Data System (MRDS). USGS ceased systematic updates to MRDS around 2011, so status and details may be out of date. Each site links to its USGS record.

Updated October 2026

Rockhounding in Hillsborough County, New Hampshire