Mt. Hamilton East Bike Climb - PJAMM Cycling

Mt. Hamilton East


Shorter, steeper route up to the Hamilton Observatory near San Jose.

Explore this Climb

PJAMM Cycling LogoDark Sky logo



If you love climbing by bike and would like more detailed information on the world’s top bike climbs, join our PJAMM Cycling group and receive our Special Edition Climb Report.
  • Receive a monthly report.
  • Get detailed and entertaining information on the greatest bike climbs and climbing areas throughout the world.
  • Discover beautiful landscapes with drone video and professional photos of remote and exotic places.
  • Gain insider knowledge on where to stay and how to conquer some of the most difficult climbs.

Climb Summary

Cycling Mt. Hamilton East

Ride 4.5 miles gaining 1,962’ at 8.3% average grade.

Both sides of Mt. Hamilton end amidst University of California observatories.

Aerial drone view of the top of Lick Observatory

“The Climb Less Traveled” -- well, at least by comparison to Mt. Hamilton West.  For those intent on maximizing their elevation and minimizing their miles, the 46 mile out-and-back, starting from Alum Rock Boulevard/Mt. Hamilton Road/San Antonio Road and back is the way to go.  Our Garmin read 6,421’ of climbing at the end of that out-and-back.  

Beginning of Mt. Hamilton East road bike climb - road sign and road.

Start of climb -- where the road pitches up.

Curvy roadway on climb up Mt. Hamilton east to Lick Observatory Silicon Valley

This is the middle climbing segment of the popular but brutal Devil Mountain Double which is held in April each year. This climb has close to double the pitch as the “front” side of Hamilton (this ascent is referred to locally as Hamilton Backside) at 8.3% and is quite challenging.  The views predominantly to the north as we climb are of hundreds of miles of the Diablo Mountain Range.  This climb ends 0.7 miles short of Hamilton West, and this final stretch is rollers with -62’ and only +27’ for that stretch.

Mt. Umunhum is visible as we climb the final segment of Mt. Hamilton West.

The summit for the Mt. Hamilton West climb is the Lick Observatory, owned and operated by the University of California.  This is the world’s first permanently occupied mountain-top observatory (the sign on the first building we come to at the top says “Residents Dining Hall” -- inactive as of 2015).

Biking Mt. Hamilton West - Lick Observatory entrance. Cyclist riding past front of Lick Observatory.

Lick Observatory at the top of the climb.

   Dome of the Lick Observatory after Mt. Hamilton bike bicycle ride.

View northwest.

Roadway Surface and Traffic Report:  The roadway is wide (but with no bike lane) and in excellent condition.  Traffic is not a problem.  This is an excellent and safe climb.

Mt. Hamilton is in the Diablo Mountain Range and it is reported that on clear days one can see the Santa Cruz Mountains, Monterey Bay, and Yosemite National Park (see, Wikipedia - Mt. Hamilton).  Unfortunately, on two of our times up Mt. Hamilton we were in the clouds much of the trip, and on the other we were suffering at about the halfway point of the Devil Mountain Double (not a time to truly relax and enjoy the views!).


Mt. Hamilton is the most featured mountain climb in the history of the Tour of California, having been featured six times between 2006-2019.  Mt. Hamilton has never been a mountain-top finish in the ToC. (Note that ToC is on hiatus for 2020.)

  • 2008 Stage 3:
  • Queen Stage - Modesto - San Jose
  • 102.7 mile, 8,039’; eastern approach
  • Stage winner Robert Gesink (NED)
  • 2011 Stage 4:
  • Livermore to San Jose
  • 81.8 miles, 8,337’; eastern approach
  • Chris Horner (USA)
  • 2014 Stage 3:
  • San Jose to Mount Diablo
  • 107 miles, 10,574’; western approach
  • Lawson Craddock (USA)
  • 2015 Stage 3:
  •  East San Jose - San Jose
  • 105.5 miles  10,200’; eastern approach
  • Toms Skujiņš (LAT)
  • 2017 Stage 2:
  • Modesto to San Jose
  • 89.8 miles, 8,064; eastern approach
  • Rafal Majka (POL)
  • 2019 Stage 3:
  • East Stockton to Morgan Hill
  • 128.6 miles; eastern approach.
  •  Rémi Cavagna (FRA)

2019 Stage 3 Profile: May 14, 2019, 128 miles / elevation gain 9,667’

Peloton makes its way up Mt. Hamilton West -- 2014 Stage 3.


Beginning of Mt. Hamilton West bicycle climb

Sunset from Lick Observatory.