3 ms·Mt. Diablo is in Contra Costa County, not Oakland.by thedookmaster 5y agoMt. Diablo is in Contra Costa County, not Oakland.vosper 5y agoAnd at the right time of year there are tarantulas everywhere. Awesome spot.meristem 5y agoLoads of NOPE, thank you.bjterry 5y agoThanks for the correction. It felt a lot closer, but I haven't been there in a long time.