It connects the Los Angeles Basin with the San Gabriel Mountains and the Victor Valley in the Mojave Desert.

The definition is subdivided into four sections as former portions of Route 2 have been relinquished by the state to the cities of Santa Monica, Los Angeles, Beverly Hills and West Hollywood.

At Holloway Drive, in the middle of West Hollywood, Santa Monica, now north of Melrose Avenue turns to the east.

Leaving La Cañada Flintridge at an altitude of 1,300 feet (400 m), the route turns north onto the Angeles Crest Highway.

The eastern portions of the Angeles Crest Highway are notoriously dangerous, with many switchbacks and blind curves, and are often closed during occasions of heavy winter snowfall.

The highway is generally closed between Islip Saddle and Vincent Gap from mid-December to mid-May due to snow and rockfall.

However, for a variety of political reasons, the department never reached agreement with Beverly Hills to build the segment through that city.

At one time, the department considered building a cut-and-cover tunnel under Beverly Hills, but even this proved a non-starter, and the freeway plan west of Route 101 was quietly cancelled in 1975.

[18] In the 1960s, the city of Beverly Hills had begun a transition from a quasi-exurban retreat for the entertainment industry to its current status as one of the world's premier shopping and culinary destinations.

Moreover, it was feared that a freeway would exacerbate the already evident divisions between the fabulously wealthy residents of the hilly areas north of Santa Monica Boulevard and the merely affluent ones to the south.

A proposed cut-and-cover tunnel for the freeway failed to generate sufficient political support, and by the mid-1970s the project was essentially dead.

For many Century City workers who live in Los Angeles' eastern suburbs, the quickest way home takes them through the residential district of Cheviot Hills, which has caused consternation among its well-heeled residents.

For Beverly Hills, the decision helped preserve much of its emergent downtown, but at the cost of creating gridlock on Wilshire Boulevard and I-10.

[dubious – discuss] The first segment of freeway was built in the 1950s and ran from just west of the Los Angeles River to Avenue 38 in Glassell Park.

[21] Except for a short portion at its eastern end, Santa Monica Boulevard was adopted as a state highway in 1933.

Route 2 continued on the Glendale Freeway to a temporary connection with Fletcher Drive at Avenue 38 in the Atwater district of Los Angeles.

From the temporary connection, the route ran northeast on Fletcher Drive, and north on Verdugo Road to its south intersection with Cañada Boulevard in Glendale.

[2] Today, the California Transportation Commission is relinquishing the street-running parts of Route 2 to local cities which it runs through.

In 1996, state law was changed to permit the relinquishment of Route 2 in Santa Monica and West Hollywood.

During this five year period, the section from just north of the 134 Ventura freeway to approximately Mountain St (Glendale College) was not built.

During this time, the closed freeway and an on/off ramp at Verdugo Blvd in Montrose were used as a location for several films due to its relatively complete construction status, and its proximity to major movie studios in Southern California.

The transition overpass from the eastbound Ventura Freeway to the northbound Glendale Freeway was prominently featured in the notorious disaster film Earthquake when a livestock truck and two cars crash over the side of the overpass (a shot completed in miniature special effects).

Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, based on the alignment that existed at the time, and do not necessarily reflect current mileage.