Waves of settlers brought in by the gold rush populated the lowlands around the San Bernardinos, and began to tap the mountains' rich timber and water resources on a large scale by the late 19th century.

Four major state highways and the California Aqueduct traverse the mountains today; these developments have all had significant impacts on area wildlife and plant communities.

The range divides three major physiographic regions: the highly urbanized Inland Empire to the southwest, the Coachella Valley in the southeast, and the Mojave Desert to the north.

Parts of the San Bernardino Mountains have annual precipitation totals in excess of 40 inches (e.g. Lake Arrowhead and Barton Flats areas), and provide an important water resource for the coastal plain below.

[18] Because of their large, steep rise above the surrounding terrain, the San Bernardinos have been subject to great amounts of erosion that have carved out numerous river gorges.

These included the Tongva, who occupied the Inland Empire area southwest of the mountains; the Cahuilla, who lived in the Coachella Valley and Salton Sea basin; and the Serrano and Chemehuevi peoples, whose territory comprised land north and northeast of the San Bernardinos, adjacent to the Mojave Desert.

[22] Indigenous peoples traveled into the mountains in the summer to hunt deer and rabbits, gather acorns, berries and nuts, and seek refuge from the desert heat.

[24] San Gorgonio Pass, which forms the largest natural break in the Transverse Ranges, also allowed interaction between coastal and desert tribes.

In 1769, the Spanish government began an effort to bring what they called Alta California under their control and introduce Christianity to native peoples through the construction of missions.

[34] In 1820, a 12-mile (19 km)-long irrigation ditch or "zanja" was dug using Native American labor to furnish water from Mill Creek, a major stream flowing out of the San Bernardinos, to the estancia and surrounding croplands.

Wilson's expedition opened the interior of the San Bernardinos to later exploration, and discouraged Native Americans such as the Mohave from staging similar raids over the mountains.

The Mormons bought and subsequently split up Rancho San Bernardino, and greatly improved the area's agricultural production by bringing in thousands of head of livestock and overhauling the local irrigation network.

[39] In order to obtain lumber for their settlements, they also began the first large-scale logging operations in the San Bernardino Mountains, starting in the Mill Creek valley.

By 1854, six lumber mills were in operation in the mountains, some as high as the crest of the range three-quarters of a mile above San Bernardino, accessed by a twisting road through Waterman Canyon.

[43] Belleville even exceeded the population of San Bernardino itself for a short time and narrowly lost to the latter city for election as the county seat.

Although another major gold strike was made in that same year, area deposits petered out by the 1880s, and the mountains were quickly depopulated, with most of the miners settling down in the San Bernardino Valley and the Mojave Desert near present-day Hesperia.

An unintended effect of the lake was to dramatically increase tourism in the San Bernardino Mountains, and its shores were developed with lodges and visitor facilities by the 1920s.

[48] Originally proposed in 1891 by the Arrowhead Reservoir and Power Company – and reportedly inspired by the success of the Big Bear Lake project – Lake Arrowhead was to be one of a series of three reservoirs that would divert water draining off the northwestern San Bernardino Mountains into the San Bernardino Valley, and furnish water to a 260 KW hydroelectric plant.

Most early tourists arrived by stagecoach, though in time the old Mormon logging road through Waterman Canyon was overhauled, allowing for the passage of automobiles.

The Seven Oaks Camp was established on the banks of the Santa Ana River in 1890, and resorts also grew up at Crestline and Running Springs in higher regions of the San Bernardino Mountains.

Conflicts occurred between those who believed that the automobile could provide fast and cheap transportation up the steep grades of the mountains, and those who worried that cars were dangerous and would cause accidents with the stagecoaches then in use.

[57] By 1911, cars had largely replaced horse-drawn carts as the primary mode of transport in the mountains, and new toll roads were constructed through the range to service them.

The largest and most famous road through the San Bernardinos – California State Route 18, more popularly known as the Rim of the World Highway for 107 miles (172 km) as it winds through the mountains – was dedicated on July 18, 1915.

In 1969, the U.S. Army Corps of Engineers deemed the Santa Ana the greatest flood threat in the United States west of the Mississippi River because of its course through heavily developed areas.

[71] Black bears roam the highlands today, but they are not native to the region: they were imported from the Sierra Nevada by the California Department of Fish and Game in the 1930s, in part to attract tourists to the mountains.