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Mountain biking trails

Contra Costa County

Black Diamond Shaft – Stewartville Trail loop from Deer Valley High School

Mountain biking trails

Contra Costa County

Black Diamond Shaft – Stewartville Trail loop from Deer Valley High School

Moderate

4.9

(8027)

13,654

riders

Black Diamond Shaft – Stewartville Trail loop from Deer Valley High School

03:19

32.4km

880m

Mountain biking

Moderate mountain bike ride. Good fitness required. Suitable for all skill levels. The starting point of the route is accessible with public transport.

Last updated: August 3, 2026

Tips

Includes a very steep uphill segment

You may need to push your bike.

After 9.16 km for 1.04 km

Waypoints

A

Start point

Bus stop

1

11.2 km

Black Diamond Mines Regional Preserve

Highlight • Historical Site

This preserve is a treasure trove of history, home to the remnants of three mining towns, including former coal and sand mines. The park features include an underground visitor center, …

Tip by

2

12.5 km

Rose Hill Cemetary

Highlight • Historical Site

The Rose Hill Cemetery is a site of historical significance that commemorates the memories of the miners and their families who once resided in this area. It pays tribute to …

Tip by

3

15.1 km

Jim's Place

Highlight • Cave

This unusual little underground dwelling's origin is unknown. From the interior, you can see a round stovepipe hole, a square skylight and a shelf opening.

Tip by

4

15.5 km

Black Diamond Shaft

Highlight • Historical Site

This once 150 feet deep air shaft was put in place to ventilate a coal mine to keep it free from dangerous gasses. There is a short tunnel to access …

Tip by

5

22.2 km

Stewartville to Ridge Trail climb

Highlight (Segment) • Climb

This steep portion of the trail provides a few switchbacks to ease the grade before reaching the Ridge Trail. There is a rest bench at the junction which is an …

Tip by

6

26.3 km

Stewartville Trail

Highlight (Segment) • Trail

The Stewartville Trail starts just south of the parking lot and runs through the preserve from east to west, linking the former Somersville and Stewartville mining towns. The route gradually …

Tip by

B

32.4 km

End point

Bus stop

Way Types & Surfaces

Way Types

15.6 km

8.19 km

6.23 km

2.31 km

109 m

Surfaces

15.3 km

9.51 km

4.90 km

2.31 km

202 m

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Elevation

Nothing selected – click and drag below to see the stats for a specific part of the route.

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Weather

Powered by Foreca

Today

Wednesday 21 October

21°C

14°C

63 %

Additional weather tips

Max wind speed: 9.0 km/h

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