Indian Grinding Rock is a rock formation in the Sierra Nevada mountain range of northern California, United States. The 548-acre (224ha) park lies on both sides of the Tuolumne River at an elevation of 732 feet (223m). It features about 100 grinding holes up to 50 feet (15m) deep with flat bottoms and vertical walls that are shaped like teardrop pits or hourglass pits. These pits were formed by natural processes, not by humans, and no evidence of prehistoric technology has been found here.
The site was designated a National Historical Landmark in 1960. The “rock” consists largely of quartzite, a hard igneous rock which makes up the foothills of the Sierra Nevada from east to west across the state line into Nevada. This area was once covered by volcanic ash, but this theory cannot explain all the features seen at the site, as some areas show little sign of volcanic activity. Instead, it appears that the harder stone was ground down by stones dragged around by glaciers, leaving these characteristic depressions behind.
There are several possible explanations for why these unique features were created. One possibility is that they were made by Neolithic people who used smaller, more easily obtained raw materials available locally to make jewelry and tools. Another explanation suggests that they were made by Native Americans using their sophisticated hunting techniques and knowledge of plant chemistry to create arrowheads and other artifacts out of stone. However, this idea is inconsistent with the fact that Indians did not leave any archaeological record at the site. A third hypothesis holds that they were made by medieval Muslims visiting the region to perform religious rituals concerning food offerings to their god Allah.
According to one legend, during the Crusades, a group of Muslim visitors to the region brought with them a set of grindstones to be used in prayer. Although there is no physical proof that this ever happened, the story explains well the origin of the name “grinding rock”. In modern times, the site’s reputation as a tourist attraction stems from its use as a location in many films and television shows; it has appeared in movies such as Westworld, TV series including Hannibal, Lost Girl, Supernatural, and The Finder, music videos such as Katy Perry’s “Roar”, and commercials for Mountain Dew BKX.
The park offers hiking trails, picnicking facilities, and scenic views. The park includes 1/2 mile long paved trail leading to the main feature called Indian Grinding Rock. From the parking lot, two paths lead away from the rock. One leads past a waterfall called Little Falls, the other goes straight ahead to what will become our campsite. Beyond the rock itself are three distinct peaks, each with a view of Table Mountain, Redding hills, and distant Mount Shasta. To the north are Napa Valley, Lake Tahoe, and the towering peak of Castle Crags, which is part of the larger Calaveras Range. On clear days, Half Dome can be seen to the northeast, though it is hidden beneath the curve of the earth. To the southwest, beyond Highway 299, are Stony Point and Big Basin Redwoods State Park, with Diamond Creek visible running between the two parks and into the Pacific Ocean.
Views of the entire landscape are possible from every point within the park. On sunny summer mornings, the reflection from the snowfields atop Mt. Shasta may be glimpsed off to the northwest. The park is located 3 miles (4.8km) south of Interstate 5, 9 miles (14km) southeast of Redding, and 12 miles (19km) west of Fort Bragg. Parking costs $6 per vehicle. No dogs allowed on the trail or at the rock. No horses allowed on the trail. No bicycles allowed on the trail. No weapons permitted on the trail or at the rock. Violators will be subject to prosecution.
The only access to the rock is via the parking area. No admittance except by permit issued by the park staff. No alcoholic beverages permitted on the premises. No fires allowed on the grounds. Camping overnight in your car is prohibited. Overnight accommodations are available at Twin Lakes Campground. Reservations are required. Group camp sites are available.
Over 200 camping spaces are available such as:
- Tent & RV sites
- 30 tent & RV sites
- 16 cabins
- 2 yurts.
All sites and cabins have access to electricity. Water is provided in all sites and cabins. Modern restroom facilities are provided in the group camp and youth group camp. Potable water is available at hand pumps. Unpotable water is available in the comfort station. No swimming or fishing is allowed in the lake. Boats are restricted to travel in the channel. No wakeboarding or waterskiing. Motorized boats must be powered by electric motors only. Non-powered boats may either be rowboats or sailboats.
Canoes, kayaks, paddleboats, rowboats, and bikes are available to rent. Picnic tables and fire rings are common sights around the perimeter of the park. Other locations include grassy knolls, mountaintops, and forest edges. Approximately 20% of the campsites are pet friendly. Pets are not recommended in cabin zones or close to trails. No animals of any kind are allowed on the trail or at the rock. Horses allowed on certain parts of the trail. Dogs allowed on the beach. No smoking anywhere in the park. Tobacco spit wads are available at the comfort station. Alcoholic beverages are available at the bar. Wine coolers, soft drinks, and bottled water are common items consumed at the bar.
On June 22, 2019, a large crack in the rock face near the summit caused by vandals in the late 1990s widened enough to allow five climbers access to the top of the formation. Access to the site was closed until further investigation could take place. Indian Grinding Rock State Historic Park was established in 1959. The land had previously been owned by the McDonald family, whose heirs sold it to the state in 1956.
At the time, most of the property was forested, but the owners later divided the land among themselves, with much of it going to Tomales Bay Area residents Murray and Betty Dimmick. Mr. Dimnick died in 1963, after which his wife donated half of her share of the property, approximately 140 acres, to the state, along with another 120 acres she had inherited from her father. She specified that the gift should go to a park dedicated to public recreation.
Indian Grinding Rock became a popular destination for local inhabitants, particularly those living in nearby towns. Visitors would drive up to the ridge of the hill to picnic, drink coffee, and smoke cigarettes while gazing out over the countryside. When the owner of the property, Mrs. Dimmick, died in 1968, the remaining acreage went through various private landownerships before being purchased by the City of Tiburon in 1976 and then transferred to the State Parks Department in 1979.