▁other ▁smaller ▁ports ▁on ▁the ▁Sac r amento – San ▁Jo aqu in ▁River ▁D elta . ▁ ▁Geography ▁San ▁Pablo ▁Bay ▁was ▁named ▁after ▁Ran cho ▁San ▁Pablo , ▁a ▁Spanish ▁land ▁grant ▁given ▁to ▁colonial ▁Al ta ▁California ▁sett lers ▁in ▁ 1 8 1 5 , ▁on ▁the ▁bay ▁at ▁the ▁site ▁of ▁the ▁present - day ▁city ▁of ▁San ▁Pablo . ▁The ▁bay ▁is ▁approximately ▁ ▁across ▁and ▁has ▁an ▁area ▁of ▁approximately ▁. ▁ ▁The ▁bay ▁receives ▁the ▁waters ▁of ▁the ▁Sac r amento ▁and ▁San ▁Jo aqu in ▁rivers , ▁via ▁Su is un ▁Bay ▁and ▁the ▁Car qu ine z ▁Stra it ▁on ▁its ▁n ortheast ▁end , ▁and ▁it ▁connect s ▁to ▁the ▁Pacific ▁Ocean ▁via ▁the ▁San ▁Francisco ▁Bay ▁on ▁its ▁southern ▁end . ▁The ▁bay ▁is ▁heavily ▁s ilt ed ▁from ▁the ▁contributions ▁of ▁the ▁two ▁rivers , ▁which ▁themselves ▁d rain ▁most ▁of ▁the ▁Central ▁Valley ▁of ▁California . ▁ ▁San ▁Pablo ▁Bay ▁also ▁receives ▁the ▁waters ▁of ▁Son oma ▁Creek ▁through ▁the ▁Nap a ▁Son oma ▁Marsh , ▁San ▁Rafael ▁Creek , ▁and ▁the ▁Pet al uma ▁River ▁directly , ▁and ▁the ▁Nap a ▁River ▁which ▁flows ▁into ▁the ▁Car qu ine z ▁Stra it ▁via ▁the ▁Mare ▁Island ▁Stra it ▁near ▁its ▁entrance ▁into ▁the ▁bay . ▁ ▁All ▁trib ut aries ▁except ▁for ▁Son oma ▁Creek ▁are ▁commer cially ▁navig able ▁and ▁maintained ▁by ▁the ▁U . S . ▁Army ▁Corps ▁of ▁Engine ers . ▁ ▁Two ▁pen ins