- Location: 39400 Clinton Keith Road, Murrieta. From Interstate 15, take the Clinton Keith Road exit (68). Turn left if you are coming from the south or right if you are coming from the north. Follow Clinton Keith Road 4.1 miles to the Santa Rosa Plateau Ecological Reserve visitor center, a dirt lot on the left side of the road. The entrance fee is $4 per adult or $3 per child (ages 2-12).
- Agency: Santa Rosa Plateau Ecological Reserve (Riverside County Parks)
- Distance: 8.8 miles
- Elevation gain: 750 feet
- Difficulty Rating: PG-13 (distance)
- Suggested time: 4 hours
- Best season: December – May
- Dogs: Not allowed (leashed dogs are allowed in the Sylvan Meadows area of the reserve, across the street from the visitor’s center)
- Cell phone reception: Weak to none for most of the route; good at Monument Hill and in a few other spots
- Water: Fountains at the trail head
- Restrooms: Chemical toilets at the trail head and at the adobes
- Camping/backpacking: None
- Recommended gear: sun hat, sunblock
- More information: Trip descriptions (slightly different route) here and here; Hiking Project page here; preserve Trip Advisor page here
- Rating: 8
Updated December 2018
This loop explores the lightly traveled southeastern corner of the Santa Rosa Plateau Ecological Reserve. Highlights include a visit to the park’s historical adobes and views from Monument Hill, but the quiet moments in between are as much of an attraction. During the cooler months, the Reserve is a popular hiking destination among locals and even hikers who drive some distance to get a glimpse of California as it was, but comparatively few hikers venture beyond the adobes to the Punta Mesa Trail.
The route described below, which can be done with any number of variations, leaves from the visitor center. The loop involves multiple trails but the preserve is well signed and maps are usually available at the trail head so navigation is not likely to be a problem. From the back of the parking lot, take the Waterline Road trail for 0.2 mile to a four-way junction with the Granite Loop. For now, stay straight Waterline Road (the left fork, part of the Granite Loop, is your return). In another 0.7 mile, reach a T-junction and head right on the Tenaja Truck Trail, a fire road that wanders through a meadow dotted with sycamores and one of the Preserve’s signature species, the Engelmann Oak.
You reach another junction in 0.8 mile. Turn left onto the single-track Lomas Trail, which makes the first significant climb of the route. At the top of the hill, a bench provides a view of the meadow below. Soon after, you reach a junction with Monument Hill Road. You can shorten the hike by heading left toward Monument Hill but for this route, bear right. Follow Monument Hill Road 0.2 mile to the next leg of the Lomas Trail on the left. It descends through oaks and chaparral before reaching the adobes, just over three miles from the start. Dating back to the 1840s and 50s, these are believed to be the oldest buildings in Riverside County. Picnic tables nestled beneath the oaks make for an ideal rest spot.
After relaxing and checking out the sights, pick up the Adobe Loop Trail in back of the buildings. If there has been recent rain and you have time, you can explore the preserve’s famous Vernal Pools by heading uphill, but to continue with this route, head left and follow the Adobe Loop Trail half a mile to the Punta Mesa Trail. This single-track drops into the oak-shaded canyon of De Luz Creek before gradually climbing through a meadow to rejoin Monument Hill Road.
Here, turn left and climb uphill to a junction with the Vista Grande Trail, your return route. To reach Monument Hill, follow the road west for half a mile to a spur leading to the top. At 2,046 feet, Monument Hill is not the highest point in the preserve – the Vernal Pools trail head is 2,080 feet – but on clear days, the view are outstanding, including Mt. Baldy, San Gorgonio, San Jacinto, the Palomar Mountains, Cuyamaca Peak and the ocean.
After enjoying the views, retrace your steps to the Vista Grande Trail and follow it downhill. After passing Waterline Road, the trail splits and rejoins at the Granite Loop. Turn left and follow the Granite Loop Trail back to Waterline Road and then the parking lot.
Text and photography copyright 2018 by David W. Lockeretz, all rights reserved. Information and opinions provided are kept current to the best of the author’s ability. All readers hike at their own risk, and should be aware of the possible dangers of hiking, walking and other outdoor activities. By reading this, you agree not to hold the author or publisher of the content on this web site responsible for any injuries or inconveniences that may result from hiking on this trail. Check the informational links provided for up to date trail condition information.