> I mean you can die on that hill, but I'd hazard a guess that nearly everyone considers SF a part of Silicon Valley
Well, unless you're from the SF Bay Area (or just Bay Area). SF is a city. SF Bay Area (or just Bay Area) is a broad region. Silicon Valley is San Jose, Sunnyvale, Santa Clara, Redwood City, Mountain View, Palo Alto, Menlo Park, and Cupertino.
Also: https://duckduckgo.com/?t=ffab&q=SF+vs+silicon+valley&ia=web
For anyone in the Bay Area, Silicon Valley is some ways south of San Francisco.
That said, a lot of startups are in SF, because Silicon Valley is too expensive (though SF itself is catching up because of the second dot com boom/bubble), so it's not surprising that outsiders lump the two of them together as a hub of Bay Area tech activity (which they are.. but they're just two distinct geographical areas).