I am looking for an outdoor performance venue in central Marin County,
California, preferably with a band shell. It should be able to seat
around 200 people, with room for 1 or 2 hundred more sitting on the
grass.

Hi mjmccall,

I'm going to post this as a comment rather than an answer since I
can't find what I am looking for online. But I think your best bet
will be Lagoon Park at the Marin Civic Center.

It will accomodate many more than the 200 you mention and I am
*almost* sure there is a bandshell there having seen many concerts at
this venue over the years. But I can't recall for sure, nor find a
definitive picture online.

I also believe there is a band shell on Mt Tam, but I think it is for
plays only and not live music.

Hopefully some other researcher will drop by with more definitive
information for you.

Regards,

-=clouseau=-