A seasonal river, the Tujunga Wash, drains much of the western facing San Gabriel Mountains and passes into and then through the Hansen Dam Recreation Center in Lake View Terrace.

It flows south along the Verdugo Mountains through the eastern communities of the valley to join the Los Angeles River in Studio City.

Mulholland Drive, which runs along the ridgeline of the Santa Monica Mountains, marks the boundary between the valley and the communities of Hollywood and the Los Angeles Westside.

In this Mediterranean climate, post-1790s European agriculture for the mission's support consisted of grapes, figs, olives, and general garden crops.

[6] The San Fernando Valley has a subtropical/hot-summer Mediterranean climate, with long, hot, dry summers, and short, mild winters, with chilly nights and sporadic rainfall.

More recently, statewide droughts in California have further strained the San Fernando Valley’s and Los Angeles County’s water security.

"[10] The Tongva, later known as the Gabrieleño Mission Indians after colonization, the Tataviam to the north, and Chumash to the west, had lived and thrived in the valley and its arroyos for over 8,000 years.

[11] They had numerous settlements, and trading and hunting camps, before the Spanish arrived in 1769 to settle in the Valley, including the village of Pasheeknga.

B. Lankershim and Isaac Van Nuys, which became very productive for their San Fernando Homestead Association that owned the southern half of the valley.

[23][24] They continued until the next increment of development converted land use, with postwar suburbanization leaving only a few enclaves, such as the "open-air museum" groves at the Orcutt Ranch Park and CSUN campus.

[25][26] Henry E. Huntington extended his Pacific Electric Railway (Red Cars) through the Valley to Owensmouth (now Canoga Park).

The Suburban Home Company laid out plans for roads and the towns of Van Nuys, Reseda (Marian), and Canoga Park (Owensmouth).

World War II production and the subsequent postwar boom accelerated this growth so that between 1945 and 1960, the valley's population had quintupled.

In addition, damage to several major freeways serving Los Angeles choked the traffic system in the days following the earthquake.

In 1997, Assemblymen Bob Hertzberg and Tom McClintock helped pass a bill that would make it easier for the Valley to secede by removing the City Council veto.

Though the state rejected the idea of Valley-based districts, it remained an important rallying point for Hertzberg's mayoral campaign, which proved unsuccessful.

According to the San Fernando Guide, the change helped develop a "primarily lower to middle-class suburb into … a collection of art and a home for the artists who ply their trade in the galleries, theaters and dance studios in this small annex.

On November 2, 2007, the City Council of Los Angeles approved a motion renaming a larger portion of Van Nuys to Lake Balboa.

[40] By 2017, numerous urban development projects began in the valley, mainly in the Los Angeles neighborhoods of North Hollywood, Panorama City, and Woodland Hills.

The valley was previously known for advances in aerospace technology and nuclear research by companies such as Lockheed, Rocketdyne and its Santa Susana Field Laboratory, Atomics International, Litton Industries, Marquardt, and TRW's predecessor Thompson Ramo Wooldridge.

The pornography industry began to decline by the mid-2000s, owing, for the most part, to the growing amount of free content on the Internet, which undercut consumers' willingness to pay.

Busch Gardens, an amusement park in the Van Nuys neighborhood of Los Angeles, was located at the Budweiser brewery.

The San Fernando Valley is home to numerous neighborhood city parks, recreation areas and large Regional Open Space preserves.

The valley falls into five congressional districts: the 25th, 28th, 29th, 30th, and 33rd,[58] represented respectively by Mike Garcia (R), Adam Schiff (D), Tony Cárdenas (D), Brad Sherman (D), and Ted Lieu (D).

Subway, dedicated transitway, and express and local buses, provided by many agencies, serve the San Fernando Valley.

Some of the former rights-of-way of the Pacific Electric Railway, which first accelerated population growth in the Valley,[60] have been repurposed for busways and light rail lines.

Metro approved a new light rail line, the East San Fernando Valley Light Rail Transit Project that will run north–south on Van Nuys Boulevard from the G Line Van Nuys station to the Sylmar/San Fernando Metrolink station, however will be built in two phases.

The Van Nuys–Airport FlyAway Terminal provides nonstop scheduled shuttle service to LAX and back to the valley, with parking.

Despite the San Fernando Valley's reputation for sprawling, low-density development, the valley communities of Panorama City, North Hollywood, Van Nuys, Reseda, Canoga Park, and Northridge, all in Los Angeles, have numerous apartment complexes and contain some of the densest census tracts in Los Angeles.

Other San Fernando Valley neighborhoods such as North Hollywood, Panorama City, and Arleta now have poverty rates which are higher.