Where does "the valley" start in the context of Los Angeles?

I’d say the physiographic southern border is basically Ventura Blvd, which runs along the base of the Santa Monica mountains.

The communal southern border is Mulholland Drive, which traverses the crest of the Santa Monicas.

The southern boundary is the Santa Monica mountains, where the 405 goes over the hill after crossing 101 in Sherman Oaks, and also where 101 turns south to go into Universal Studio.

Thanks, I am going to take a good look at a map tonight. My friends (who live in the LA area) tend not to agree on where the Valley starts.

@elbanditoroso

As you may be able to determine from this map, much of the Valley is within the Los Angeles city limits.

What are your friends’ opinions on where the valley starts?

@Brian1946

One of them said it was (on the 101) just as you are coming down off the mountains. By the time you hit Universal City, you’re in the valley.

I can sort of see why you wrote “Ventura Blvd.” because that seems to run right up to the foothills – is that correct?

What about Glendale and Pasadena? Seems like those could be included in the valley, or not.

@elbanditoroso

“I can sort of see why you wrote “Ventura Blvd.” because that seems to run right up to the foothills – is that correct?”

That’s close, although I’d say it runs approximately parallel to the baseline of the foothills.

“What about Glendale and Pasadena? Seems like those could be included in the valley, or not.”

I’d say the southwestern protrusion of Glendale is in the valley, and the southern protrusion is in the Cahuenga Pass, which connects the valley to the Los Angeles basin.

Pasadena is in the San Gabriel valley, which is separated from the San Fernando by the San Gabriel mountains.

Shouldn’t it be bounded by the slopes of the valley itself?

@zenvelo

I agree that it should be bounded by slopes, but I think the slopes would be those of the Santa Monica mountains.

However, the lowest slopes have been paved over, and they would have been more discernible before the paving.

Using an elevation detector, I found that the slope of the valley floor south of the LA river is about 10’ per mile, whereas it increases to about 100’/mile just south of Ventura Bvd.

@Brian1946

“I’d say the southwestern protrusion of Glendale is in the valley, and the southern protrusion is in the Cahuenga Pass, which connects the valley to the Los Angeles basin.”

Correction: I’d say the southwestern protrusion of Glendale is in the valley, and the southern protrusion is in the I5 Corridor, which connects the valley to the Los Angeles basin.

Core erection:

@zenvelo @Zaku

I agree /SNIP/ Ventura Bvd.