Before it was a park, this ridgeline belonged to the Ohlone people. Spanish explorers and Mexican ranchos displaced them as ranching took hold in Wildcat Canyon. By the late 1800s, American ranchers like the Curran family and the operators of Sweet Briar Dairy worked the land. Around 1910, Frank C. Havens' Eucalyptus, Mahogany, & Land Company planted the eucalyptus groves that still mark certain hillsides, though conservation efforts now focus on restoring native coastal scrub. The transformation to public parkland came on June 4, 1936, when the newly formed East Bay Regional Park District purchased 2,162 acres from the East Bay Municipal Utility District. The tract was initially called Upper Wildcat Canyon. Six weeks later, on July 16, it was renamed Charles Lee Tilden Regional Park, honoring the Bay Area attorney and businessman who served on the park district's first board of directors.

Tilden Park owes its character to the Depression. At the same June 1936 meeting that authorized the land purchase, the East Bay Regional Park District board appropriated $63,428 in local matching funds to unlock $1 million in federal relief money. Civilian Conservation Corps crews built roads, trails, bridges, picnic areas, and the golf course. WPA crews dammed a creek to create Lake Anza, raised stone restroom buildings, and constructed the exterior of the Brazilian Room - all from stone quarried within the park itself, near the Big Springs trailhead on South Park Drive. In 1935, Congressman John H. Tolan helped secure a $1.5 million WPA grant for the seven-mile Wildcat Canyon Road connecting Berkeley and Orinda. Then came the Golden Gate International Exposition of 1939-1940. When the World's Fair closed, the park district bought its used trash cans and benches. More valuably, Brazilian hardwood from the Brazil Pavilion was repurposed as the interior paneling of the Brazilian Room, designed by architect Gardiner Dailey. The park's aesthetic today - the stone masonry, the careful road alignments, the restroom buildings that look like they grew from the hillside - is directly descended from that New Deal era craftsmanship.

War reshaped Tilden in ways that are still visible if you know where to look. In 1942, seventy-two acres of the park's southern section were leased to the military for the Grizzly Peak VHF Station, which became headquarters for the 411th Army Air Forces Control Group overseeing coastal Northern California radar sites. Camp Wildcat Canyon housed convalescing soldiers. On Labor Day 1942, the Richmond Shipyards Athletic Association held the largest event in the park's history - a company picnic for Kaiser shipyard workers that drew 10,000 people for a day of golf tournaments, diving contests, and band concerts spanning from eight in the morning to ten at night. After the war, the U.S. Army opened an anti-aircraft installation near Vollmer Peak with 90mm four-gun batteries. It was decommissioned in the late 1950s when Nike missiles in adjacent Wildcat Canyon made the guns obsolete. The land was returned to the park district in 1959, and the barracks site became part of the Redwood Valley Railway - a 15-inch gauge miniature railroad established in 1952 that today carries 160,000 passengers a year along its 1.25-mile track. A concrete bunker from the old installation still stands, repurposed as a park maintenance facility.

Tilden accumulates treasures the way a family accumulates heirlooms. The Tilden Park Merry-Go-Round, built in 1911 and now listed on the National Register of Historic Places, was installed in 1948. The Regional Parks Botanic Garden spreads ten acres of California native plants across a shaded canyon, including rare and endangered species found nowhere else in cultivation. Lake Anza, the WPA-dammed swimming lake in the park's center, is open from April through October, with weekly water testing. The Little Farm near the Tilden Nature Area keeps shorthorn cattle, sheep, goats, rabbits, pigs, and poultry for visitors to feed and learn from. The golf course, designed by William Park Bell and built by WPA workers, opened to the public on November 11, 1937. Goats graze the hillsides each summer to manage vegetation. South Park Drive closes every year from November through March to protect migrating newts. Every element tells a different story, and together they explain why Tilden has been, for nearly ninety years, the East Bay's backyard.