[1] Located in the Mojave Desert,[4] the pass is an important link from the Greater San Bernardino Area to the Victor Valley, and northeast to Las Vegas.

[9] In 1851, a group of Mormon settlers led by Amasa M. Lyman and Charles C. Rich traveled through Cajon Pass in covered wagons on their way from Salt Lake City to southern California.

[10] Early Latter-day Saint documents, which often referred to the pass as "Cahoon Pass", suggest an alternate explanation for the name, that it is named in honor of Mormon pioneer Andrew Cahoon (pronounced similarly to Cajon), who was an early settler in nearby San Bernardino and assisted in surveying and laying out the city of San Bernardino.

[12] The weather over the pass can vary from foggy days with poor visibility to clear afternoons where aircraft are bounced by gusting Santa Ana winds that top 80 mph (130 km/h).

The mass and wing loading of an aircraft determine its sensitivity to turbulence, so what may seem violent in a Cessna 172 may seem only mild to moderate in a Boeing 747.

[14][15] Today the Union Pacific Railroad and BNSF Railway (the successor to the Santa Fe) use the pass to reach Los Angeles and San Bernardino as part of the Southern Transcon.

The 3.0% grade for a few miles on the south track is challenging for long trains, making the westbound descent dangerous, as a runaway can occur if the engineer is not careful in handling the brakes.

As of 2024, the Brightline West high-speed rail line is currently under construction in Cajon Pass as part of its route between Rancho Cucamonga and Las Vegas.

Both Path 26 and 46 provide the Los Angeles metro area with electricity generated from fossil fuel power plants in the Four Corners region, and hydroelectric dams along the Colorado River.

The following winter, rains in addition to burnt vegetation caused a number of landslides to further close the freeway pass.

[citation needed] On July 17, 2015, during severe drought conditions plaguing the whole state and creating extreme fire hazards, a fast, wind-whipped wildfire swept over Interstate 15 between California State Route 138 and the Oak Hill Road exits, sending drivers running for safety and setting 20 vehicles ablaze, officials said.

[25] The following year the Blue Cut Fire again forced the closure of the freeway for several days starting on August 16, 2016.

[27] During wind advisories, Caltrans will use its Changeable message signs to warn motorists of dangerous weather in the Cajon Pass.

[28][29] When any closure is total, California Highway Patrols often provide escorts through the pass as the Interstate 15 is a major artery for the High Desert region.