This hike travels through canyon drainages and oak savannah for a nice workout in the hills above Castro Valley. It is a loop (description is counterclockwise) that packs a surprisingly decent workout as it encircles the various subdivisions that make up the Five Canyons development. This isn't a destination hike, but certainly worth checking out if you live in the area.
Start at the trailhead at Five Canyons Park where there are 2 baseball fields and a decent-sized parking lot. Walk north on Five Canyons Parkway for approximately 1 block, cross the street at Sandstone Trail and head uphill under some transmission lines. Sandstone goes behind a subdivision before steeply heading down into thickly forested Shady Canyon.
The trail reaches a junction with the Shady Canyon Trail which runs straight uphill in one direction and down the bottom of its namesake. Take the uphill route through a cattle gate, and go 300 vertical feet in 0.3 mile until mercifully reaching the top near a water trough for cattle. You may see cattle in this area as well. Upon reaching the top of the ridge there is first a trail to the right, then the Newt Pond Trail off to the left. Take Newt Pond downhill as it goes behind some houses with nice views into the wooded canyon a few hundred feet below.
You reach the canyon bottom and rejoin Shady Canyon Trail soon enough, and cross the creek on the small earthen dam that creates Newt Pond. Shady Canyon continues downstream next to the creek until shortly after going under Five Canyons Parkway (elevated over 100' overhead) where it curves to the left/south, and crosses a small street near the end of a cul-de-sac. You are now on the Deer Canyon Trail, and it goes up and down as a fire road until ending at its junction with the Sandstone Trail. Go right onto Sandstone at the top of a small hill a few hundred yards past an information kiosk (with takeaway maps) and it curves down into the upper end of Deer Canyon then basically turns into the Diamond View Trail. Follow Diamond View as it contours around the drainage before finally heading straight uphill to Five Canyons Park.
Gate Policy: If a gate is closed upon arrival, leave it closed after you go through. If it is open, leave it open. Leaving a closed gate open may put cattle in danger. Closing an open gate may cut them off from water. Please be respectful, leave gates as found.
WARNING! Hiking and outdoor related sports can be dangerous. Be responsible and prepare for the trip. Study the area you are entering and plan accordingly. Dress for the current and unexpected weather changes. Take plenty of water. Never go alone. Make an itinerary with your plan(s), route(s), destination(s) and expected return time. Give your itinerary to trusted family and/or friends.