There are miles of dirt roads and a few footpaths in Chino Hills State Park. There are more bicycle riders than hikers, and there are occasional horseback riders. The basic scheme is that there are dirt roads along the north ridge and along the south ridge, with the road through Telegraph Canyon running between them. Footpaths and other roads join the three main routes at several points, so you can choose a route that is as easy or as hard as you want. The best climb is Gilman Peak, where you gain 800 feet in one mile. San Juan Hill is the highest point in the park, but the climb to the summit is not steep. Most of the trail intersections are marked by signs. Directions to some of the trails are given above in the topographic map section.
Hawks are very common in this area. You will often see them soaring above or perched on a fencepost. They have a shrill call that echos through the hills. Also expect to see a squirrel or two on most hikes. Other local residents include coyotes, deer, and rabbits, but you will rarely see them. Rabbits are rarely seen only because they are the favorite meal of the coyotes. I have seen bobcats on several occasions, and there is a recent reliable report of a young mountain lion in the area, although I have never seen one. Rattlesnakes are very common, and they like to sun themselves by stretching out across the trail. At dusk you will hear the yapping of a distant coyote pack, and occasionally an unmistakable owl hoot.
The hills start turning green in January, just after the seasonal rains start,
then a little later the wildflowers bloom. But after about four
months everything turns brown again. The little stream through Telegraph
Canyon runs year around in some areas. The shrubs with the
prolific clumps of red berries in winter are toyon. The berries are edible
but not very tasty. Groves of oaks and sycamores
are found in the canyons. Fennel grows head-high in some of the
grassy areas. The young shoots taste like licorice.
The plant is a garden herb gone wild, and it is unlikely that the
round gourds are native either.
Much of the park is grassland. It was a
cattle ranch before it became a state park. Weathered fenceposts survive
in some areas, and there is still a working windmill on Telegraph
Canyon road if your horse needs a drink. Bring plenty for yourself
also, as this area is hot and dry in the summer.