Campgrounds and RV parks near Diamond Bar, CA

Puddingstone Lake at Frank G. Bonelli Regional Park supports boating, fishing, swim beaches, and miles of paved and dirt trails, and the park is slated to host mountain biking events for the 2028 Olympics. Raging Waters, a large water park, sits inside the same regional park. Disneyland, Knott's Berry Farm, and Universal Studios are all within roughly a thirty to forty-five minute drive in light traffic. Chino Hills State Park protects roughly fourteen thousand acres of grassland and oak woodland with extensive trails for hiking, mountain biking, and horseback riding. The Santa Ana River Trail runs alongside Canyon RV Park and connects more than fifty miles of paved bikeway from Huntington Beach to San Bernardino. Up in the San Gabriel Mountains, the East Fork of the San Gabriel River offers swimming holes, fishing, and the trail to the Bridge to Nowhere.

Diamond Bar has a Mediterranean climate with hot, dry summers and mild, wetter winters. Rain is concentrated between November and March, with February and December typically the wettest months, while June through September stays almost entirely dry. Snow is essentially nonexistent at valley elevations, though winter storms can dust the surrounding San Gabriel Mountains and briefly close East Fork Road above Azusa. Spring is the prime window for Chino Hills State Park. Wildflowers carpet the valleys from March through May, including California poppies, lupines, and mustard, and weekend campsites at Rolling M Ranch fill quickly during this peak season. Summer brings consistent daytime heat in the inland valleys, often climbing into the nineties, which pushes traffic toward Puddingstone Lake, the river canyons, and the coast. Fall is dry and warm and coincides with elevated wildfire risk across the foothills; the LA County Fair at Fairplex in late summer and early fall drives heavy demand at Fairplex RV Park and Bonelli Bluffs.

Site quality varies sharply by property. Bonelli Bluffs offers paved full-hookup pads with 30 and 50 amp service, room for slideouts, and lake views from many sites. Fairplex RV Park has paved sites with full hookups and tighter spacing typical of urban event-adjacent parks, with freeway noise nearby. Canyon RV Park sites are mostly gravel with full hookups, shaded by mature cottonwoods, and accommodate rigs up to roughly forty-five feet. Chino Hills State Park's Rolling M Ranch is primitive: paved pads up to thirty feet, no hookups, no dump station, no open fires or charcoal (gas stoves only), but with flush toilets, showers, and potable water. Camp Williams sits on a narrow, winding mountain road, so larger rigs should plan the drive carefully. Cell coverage is generally reliable in the valley parks and weaker in the canyon.