Mt. Hamilton backside road stories

The old road followed Arroyo Bayo.

The old road followed Arroyo Bayo.


One of the most wild and scenic roads in the Bay Area is Hwy 130, San Antonio Valley Road, on the backside of Mt. Hamilton.

I’ve ridden there since 1980 and it never fails to impress. Over the years I’ve wondered about that dirt road alongside Arroyo Bayo after the hill out of Isabel Creek.

Jobst Brandt, who rode on the backside of Mt. Hamilton more than any cyclist, may have mentioned riding there, but I’ve forgotten.

But Peter Locke has not forgotten, and he rode with Jobst. He told me recently by phone how they rode through the creek. He had fond memories of fording the creek numerous times, as well as crossing a reservoir. Here’s Google Maps after the Isabel Creek climb.

Red line shows where the road went.

Red line shows where the road went.

I looked at a USGS topographic map from 1955 and sure enough the dirt road that you see today along the creek was the main road.

It’s fast disappearing, but it’s still used by landowners in some sections.

I wouldn’t want to try riding there today, but back in 1956-57 when Jobst, Peter and others rode it, the road was maintained.

The road enters a narrow section.

The road enters a narrow section.


Here's where the first section of road returns to present Hwy 130.

Here’s where the first section of road returns to present Hwy 130.

USGS topo map from 1955.

USGS topo map from 1955.

Another location where the road diverged from today’s alignment was in San Antonio Valley. There’s a short incline that passes by a ranch on the right. The old road ran through the ranch property up until around 1954 when the road was straightened.

Jobst Brandt mentioned riding this segment in the early days. Potentially he could have ridden here in 1954 when he was 19, but certainly within a year or two.

Location on San Antonio Road/Valley where the old road took a right through a rancher’s property.

Former San Antonio Valley Road until about 1954 when it was realigned.

One Response to “Mt. Hamilton backside road stories”

  1. Brian Coyne Says:

    This stretch also seems to have had a different name in the past: it’s marked as “Bayou Road” on this set of 1956 Santa Clara Co maps: http://www.historicmapworks.com/Atlas/US/9516/Santa+Clara+County+1956/

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