Most California mountains were left unclimbed by the Native Americans and Californios (Spanish/Mexican early settlers). The Indians basically avoided the mountains unless strictly necessary for food or to get to the other side. The history books never explain this, but I believe it was because grizzly bears infested California’s mountain ranges until the early 20th century. People armed with bows and spears probably thought it was best to stay away from the bears, if possible.
The Spanish/Mexican indifference to the mountains is bewildering. Most of the time, they never even bothered giving them names. They were these big eternal masses on the horizon, like part of the climate. They went up some of the canyons in search of timber, but that was mostly it. When gold was discovered in the San Gabriel Mountains (at low elevation, six years before the discovery at Sutter’s Mill), that drew the attention of armies of Anglos.
It was the Anglos who swarmed all over the mountains, searching for gold and timber. Californio gold-hunters were content to set up placer mining operations in lower elevation riverbeds, but the Anglos would climb up into the mountains. There was a mine on the side of Mt Baldy, not far from the site of the current Sierra Club Ski Hut at 8,300 feet.
But some of the Anglos were interested in climbing to the tops of the mountains just to see if it could be done. This was a first. The earlier inhabitants and settlers had little known interest in doing any such thing. Only mad dogs and Englishmen go out in the midday sun, or climb mountains for no reason.
I don’t think there is a square inch of the San Gabriels and the San Bernardinos, and precious little of the Sierra Nevada, that hasn’t already been marauded over by timbermen, prospectors, sheep herders, ranchers and other assorted alpinists.