In 1769, Gaspar de Portola's expedition passed through the Los Osos Valley. Father Crespi's diary notes that the expedition saw "troops of bears (osos)" in the valley, and, since then, it became known as the Los Osos Valley. When the new Monterey mission populace faced starvation, a hunting expedition was sent to the Los Osos Valley, killed many grizzlies, and packed the meat back to Monterey, saving the people there from disaster.
Los Osos Oaks was part of a Mexican land grant that was eventually divided into farm and ranchland. Incredibly, unlike the trees in the surrounding area which were cleared away to allow for agriculture, the magnificent oaks in the park are still growing. 1.5 miles of trails over a relatively flat sandy terrain. Dwarf oaks grow in a mineral-depleted soil of "relic" sand dunes.
Poison oak can be found throughout the state reserve. Camping, fires, and dogs are not permitted. There are no restrooms or facilities for picnicking. 90 acre grove of dwarfed, 800-year-old coast live oaks on an ancient dune habitat. Located in eastern portion of the community of Los Osos adjacent to Los Osos Valley Road. Established in 1972, thanks to the Small Wilderness Area Preservation (SWAP) Foundation.