Dictionary Hill: the newest open space preserves in the county

Explore a remnant of a volcanic island that has panoramic views

Starting up from the signed trailhead
  • Starting up from the signed trailhead

The hill with the funny name has a lot of things going for it. It had been scheduled for a major housing development that would have leveled and lowered the summit by many feet. Through the efforts of the Dictionary Hill Open Space Advocates, the San Diego County Board of Supervisors voted unanimously, on November 17, 2017, to add the 175 acres to the County’s Multiple Species Conservation Plan and make it one of the newest open space preserves in the county. The area is an island of coastal sage scrub habitat that has been rapidly disappearing because of urban sprawl. The hill is home to many endangered, rare, and sensitive plants, such as the variegated liveforever (Dudleya variegata), Munz’s sage (Salvia munzii), and coast barrel cactus (Ferocactus viridescens), as well as a haven for such wildlife as the rare California gnatcatcher, San Diego horned lizard, Quino checkerspot butterfly, cactus wren, gray fox, bobcat, and several raptors.

Volcanic breccia from a debris flow

Volcanic breccia from a debris flow

The 1,059-foot peak was originally known as Lookout Mountain where early settlers would climb to check if a steamer had come into the bay before taking the 12-mile trip to the harbor to sell their produce and wares. In 1911, the Miller Publishing Company in San Francisco bought 480 acres of a subdivision called East San Diego Villa Heights on the southern side of the hill which they used for promotional purposes. A deed to a small 50- by 100-foot lot was given to those who purchased a 25-volume set of encyclopedias, so Dictionary Hill is actually a misnomer. Some sources say a dictionary may have been thrown into the encyclopedia mix. However, few purchasers took advantage of their property as the street grid did not take into account the actual topography, which was quite steep, making the narrow plots on the steep ridge unsuitable for construction. Today, most of the houses in this area are leveled in construction by using stilts.

Besides Dictionary Hill’s interesting history and importance as coastal sage scrub habitat, it is significant for the metavolcanic rocks that reveal its geologic history. They date back to 125 million years ago, when there was a chain of volcanic islands separated by a sea from the adjacent continent. Remnants of these volcanic islands are found on inland peaks, such as San Miguel Mountain, Mother Miguel Mountain, Black Mountain, the hilltops of Camp Pendleton, and Dictionary Hill. The hill also shows evidence of later volcanic activity from 29 million years ago, and again some 18 million years ago, with extrusion of volcanic flows and pyroclastic debris from volcanic vents. The resultant metavolcanic soils found on the hill provide a happy environment for some of the sensitive plants found here.

A trail plan is being developed for this new open space area. Some of the existing use trails are very steep, and trekking poles are recommended for this cherry-stem loop of Dictionary Hill. Beginning at the Barcelona Trailhead, take a diversion south and then follow a trail east to an overview of Bancroft Creek, a lush area along a canyon bottom with riparian plants. This segment of the trail has many invasive species such as tamarisk, Mexican fan palms, castor bean, eucalyptus, and Fuller’s teasel, along with native species such as laurel sumac, artemisia, and San Diego sunflower. After viewing the riparian area along Bancroft Creek, retrace your steps to the main trail where you will see a sign for Dictionary Hill. Follow the trail northwest and west. At mile 0.5, take the second steep trail up heading directly south. During the climb, note a plant that looks like black sage even though there is no black sage growing on the hill. This is Munz’s sage, a plant endemic to southern California’s coastal sage scrub habitat but found in very few places in the county.

At the top of this hill, take the trail west (left) and climb up to an open area. Note the metavolcanic rocks found here, very different in appearance from granitic rocks found elsewhere. Both are igneous rock (one of the three different rock types: igneous, sedimentary, and metamorphic). Granitic and volcanic rocks derive from molten material. The difference is in how fast they cool. Granitic rocks cool slowly underground, giving time for like minerals to come together. Volcanic rocks cool quickly as they are extruded from the depths, which does not allow enough time for like minerals to come together.

Continue climbing up the hill. At about 0.9 mile, you will be at the top of a ridge and can look down at the Dictionary Hill development. The trail will curve north and then west, following the track of the powerlines. You will begin seeing coast barrel cactus, sometimes called San Diego barrel cactus. Many of the cacti were removed by residents who wanted to plant them in their yards, but they are slowly recovering. Please do not walk off the trail onto the cryptobiotic crust. This dark, crusty soil is a slow-growing community of living organisms that can easily be disturbed or destroyed if you step on them.

Follow the trail to the summit, where there is a 360-degree view that includes the harbor, Mt. Soledad, Fortuna Mountain, Cowles Mountain, Mt. Helix, El Cajon Mountain, the Cuyamacas, Mt. Miguel, and views south toward Mexico. It is easy to see why this was called Lookout Mountain. The trail down is north, again rather steep—use caution. Bancroft Drive is to the northwest. The creek and this drive are named for western historian Hubert Howe Bancroft who had a ranch in western Spring Valley that is now the home of the Spring Valley Historical Society.

Follow the trail that curves to the east toward the water tank, passing it at about 1.8 miles. Continue down the hill heading east, and then turn south to eventually complete the loop. As you are hiking, listen for the sound of a wrentit and the characteristic call of the male that sounds like a bouncing ping-pong ball. Along the trail you will see a mix of native and non-native plants. The non-native plants include sweet fennel, which smells like licorice, and Fuller’s teasel with its spiky flowerhead. It is called teasel as the flowerhead was used to “tease” out fibers prior to spinning. The purplish-colored, tube-like flowers are protected by the spines. The non-native pine trees along this trail probably grew from seeds spread from residential landscapes along the ridge. As you complete the loop, head back down the cherry stem to the trailhead.


Explore a remnant of a volcanic island that has panoramic views.

Dictionary Hill map

Dictionary Hill map

Driving directions: (Spring Valley) From CA-94 East, exit south on Sweetwater Springs Boulevard and go 0.9 mile. Turn right onto Austin Drive and go 0.7 mile. Turn left onto S. Barcelona Street and go 0.3 mile to the end of the road and park at the Barcelona Trailhead. Hiking length: 2.5 miles. Allow 2 hours to explore the area. Difficulty: Moderate. Elevation gain 600 feet. Trekking poles recommended for steep ascents and descents. Dogs on leashes and mountain bikes allowed. No facilities.

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In the 1970's CB'ers (Citizens band radio operators) would drive their cars up to the summit to talk to people all over Southern California and sometimes farther.

In the 60's four of us drove up to Dictionary Hill crammed into a buddies tiny French car. At one point the road was too steep for the car to continue, so three us had to get out so the driver could turn the car around. Now that I think about I'm glad he did not need to do any emergency braking on the way down the hill: the brakes on that car no doubt would have failed heading down the steep hill with the weight of four high school boys. If anyone wants adventure, skip the hiking trail and try driving around the housing areas near the peaj: that will get your adrenaline flowing.

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