The so-called Main Divide, or summit ridge, of the Santa Ana Mountains straddles the boundary between Orange and Riverside Counties, definitively separating the L.A./Orange County urban sprawl from inland communities such as Corona, Lake Elsinore, and Murrieta. As you cruise up or down Interstate 15 through these inland parts, the Santa Anas off to the west appear dark, pillowy, and a bit mysterious as they rise to elevations of 3000 to 5000 feet.
Access to the northern (higher) section of the Main Divide is difficult or impossible by car, but hikers and mountain bikers can choose a number of routes, primarily fire roads that ascend either the east or west slopes. Bedford Road offers self-propelled travelers the fastest and easiest access to the Main Divide from the east (south of Corona) side of the mountain range.
Exit Interstate 15 at Weirick Road (5 miles south of Corona and 14 miles north of Lake Elsinore), then proceed southward on the west-side frontage road for exactly 0.5 mile. Here turn right (west) on unmarked Bedford Road, which is paved for a while, then dirt thereafter. Drive uphill for 2.1 miles -- if your vehicle allows -- to a gate blocking car traffic, and find a safe spot to park.
Except for a half-dozen brief flat or downhill stretches, you'll be gaining elevation steadily as you proceed up the mountainside. As you climb you'll look down on the twin ribbons of Interstate 15 running through Temescal Valley. This trough-like valley, and the Santa Ana Mountains themselves, were shaped by lateral and vertical movements along the Elsinore Fault, which extends from the Corona area, through Lake Elsinore and Temecula, and down through San Diego County's mountain and desert areas.
At about 3.5 miles into your trek, you'll cross a small flat with a couple of bay laurel trees. Take the opportunity to rest in the shade here if it's a warm day. At about four miles you come to an intersection with the Main Divide Road (fire road). Hike south about 0.1 mile farther to the top of a small knoll where the Forest Service has installed some water-collection devices for fighting fires. Here, a slice of the ocean and Orange County's coastal plain is visible on clear days. Bald Peak, about one mile farther south and a little higher, offers a somewhat better view.
Above all, enjoy that view, which from almost any place on the Main Divide includes the 10,000-plus-foot-high summits of the San Bernardino and San Jacinto Mountains in the northeast.