Santa Rosa Junior College[1]. I just looked up AMATYC rankings, and apparently they haven't placed since 2003-2004. I'm not sure if that's because of their math department degrading, or other colleges stepping up their game, or some failure at the state K12 level in supplying fundamentals (since the contest is based on student performance). It's possible my information is somewhat out of date (I went through there around 2000), but the first of my children will be making choices about colleges in a few years, and I was leaning towards recommending it (but haven't closely looked at it again recently).
From my experience at that time, it didn't feel significantly different than the campus I transferred to, except that the math classes at the Junior College were actually significantly harder, or at least more intense.
Ah, I still live there myself. A nice place to live if you can leverage something close to a SF payscale even though you're an hour north, as the housing cost is still relatively high compared to almost everywhere else in the country.