Somersville

Overview

A coal town above Antioch

Somersville developed during the 1850s as coal mining expanded in eastern Contra Costa County. It was one of five towns in the Mount Diablo coalfield, supplying labor and services to mines that sent fuel toward Bay Area markets.

Rising costs and competing fuel sources ended the coal boom. Sand mining later reused parts of the district, including workings near Somersville. The town’s houses and shops disappeared, leaving a landscape of planted trees, mine waste and cemetery graves that requires interpretation to read.

Video

Somersville in 30 seconds

Somersville was a coal town in California’s Black Diamond hills. Historic photographs and maps are dated on screen; current access is summarized in the guide.

History

How Somersville grew and changed

1. 1850sSomersville grows around the coal mines.
2. 1863A post office opens.
3. Late 1800s–early 1900sCoal mines close as costs rise and competition increases.
4. 1910The post office closes.
5. 1920s–1949Sand mining reuses workings near the old towns.
6. 1970sRegional park management begins protecting the landscape and cemetery.

On the ground

What remains at Somersville

Rose Hill Cemetery, introduced trees and mine waste mark the former settlement. The park’s townsite panel says these are the principal remains; visitors should not expect intact streets of buildings. Mine interpretation and the Greathouse Visitor Center explain the wider district.

Before you go

Access and current conditions

Use the preserve entrance on Somersville Road south of Antioch. Trails reach the townsite and cemetery; entering historic mine workings is a separate matter, allowed only through authorized park tours. Consult the park for current gate hours, visitor-center availability and tour bookings.

Reading the maps

The town in its landscape

The retained early sheets label Somersville, Nortonville and Stewartville. Later sheets show the changing park and mining landscape.

Historic maps

Somersville on USGS maps, 1896–1989

Crops from the USGS Historical Topographic Map Collection, centered on the townsite. Each sheet shows what surveyors mapped that year; compare them with today's topo and aerial on this page.

18961:62,50019431:62,50019531:24,00019891:100,000

Map & directions

Getting there

The routes below use OSRM on OpenStreetMap data. Follow the access notes above and confirm current conditions before traveling.

Base map: USGS The National Map (public domain). Routes: OSRM on © OpenStreetMap contributors data (ODbL), computed October 2026. Times assume dry roads.

Photos

Have photos of Somersville?

We haven’t added photographs of Somersville yet. If you’ve visited, share your photos and a field report below.

Visitor reports

Been to Somersville?

Been there lately? Tell the next visitor what you found: whether you could get in, the state of the road and what's still standing. Photos are welcome. We read every report before it appears here.

Thanks. Your report reached us, and we'll read it before it goes on the page.

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Nearby

Other sites near Somersville

Straight-line distance from the townsite to other mapped sites in our California index.

• Black Diamond Mines Regional Preserve0.6 mi SE · Contra Costa
• Nortonville0.9 mi W · Contra Costa
• Stewartville1.1 mi SE · Contra Costa
• Judsonville2.8 mi E · Contra Costa
• West Hartley3.0 mi E · Contra Costa
• Collinsville8.3 mi N · Solano
• Eckley19.6 mi W · Contra Costa
• Cement24.8 mi N · Solano

Sources

Sources and credits

1. Somersville, California - Wikipedia: historical chronology, identity and location; read October 25, 2026.
2. Somersville - California Ghost Town: historical fact sheet and town history; read October 25, 2026.
3. Black Diamond Mines Regional Preserve | East Bay Regional Park District: history, surviving features and visitor information; read October 25, 2026.
4. Elevation at the mapped point: USGS 3D Elevation Program query, October 25, 2026. Historical topographic sheets: USGS Historical Topographic Map Collection (public domain).
5. Road routes and step distances: OSRM on © OpenStreetMap contributors data (ODbL), October 25, 2026. Route endpoints are shown separately where they do not reach the town point; estimates do not confirm current road access.
6. East Bay Regional Park District, “Somersville Townsite” interpretive panel, read October 25, 2026: settlement dates, coal transport, mine closures, waste piles, introduced trees and Rose Hill Cemetery.

Photo and map credits

• Area base map, topo and aerial imagery: USGS The National Map (public domain).
• Historic maps: USGS Historical Topographic Map Collection (public domain): Mt Diablo 1896, 1:62,500; Mt Diablo 1943, 1:62,500; Antioch South 1953, 1:24,000; Stockton 1989, 1:100,000.