Native people have lived in the vicinity of Portola Redwoods State Park for thousands of years. The Santa Cruz Mountains and San Francisco Peninsula were home to a mosaic of tribes. The Quiroste (pronounced Ki-raw’-stee) people comprised the largest indigenous group; their territory ranged from what is now Año Nuevo to Pescadero and up towards Skyline Ridge, including today's Portola Redwoods State Park.

Here, the Quiroste fished for steelhead trout and coho salmon, and they collected naturally forming asphaltum (tar) from Tar Creek to use as an adhesive and sealant. Olivella sea-snail-shell beads from the coast were used to barter and trade with inland tribes. Trading involved travel along established routes; one route passed through this park. Abalone, mussels, fish, and other seafoods—plus flint used to chip sharp stone knives, spears, and arrowheads—were among the coastal resources they traded. In return, inland foods and such materials as obsidian for stone tool making and bows from distant lands were brought to the Quiroste over mountain trails. 
Portola Redwoods State Park is named for the Spanish explorer Gaspar de Portolá. In 1769, the Portolá expedition traveled overland along the San Mateo coast to the San Francisco Bay, without actually reaching this spot. This journey, along with several others that soon followed, led to Spanish settlement of the San Francisco and Monterey Bay areas.

California’s Gold Rush of 1849 fueled a demand for ever-increasing amounts of timber for mining and construction. Lumberjacks came to the Santa Cruz Mountains, cutting what seemed to be unending groves of thousand-year-old redwoods.

The first European settler, Danish immigrant Christian Iverson, split redwood shakes for a living. He built a cabin along Pescadero Creek in the 1860s. In 1889, Iverson sold his property to William Page, a successful lumberman. Page ran a shingle mill just east of the present-day Slate Creek trail camp. He also established a haul road connecting several mills to the Embarcadero in Palo Alto. This haul road, later named Page Mill Road, still exists today.
In 1924, San Francisco businessman John A. Hooper sold over 1,600 of these wooded acres to the Masonic Lodge’s Islam Shrine of San Francisco for a summer retreat. The Shriners built cabins, kitchens, a stage, and a recreation hall--the present-day visitor center. When membership dropped, the lodge sold the property to the State of California for $112,500, gifting half of its appraised $225,000 value. In 1945, Portola Redwoods State Park officially opened. The park has since doubled in size, due to the efforts of such donor organizations as Save the Redwoods League.