Russian River thumb|Goat Rock Beach as viewed from the Jenner Cliffs looking south, showing the mouth of the Russian River at the Pacific Ocean Much of central and northern Sonoma County is in the watershed of the Russian River and its tributaries. The river rises in the coastal mountains of Mendocino County, north of the city of Ukiah, and flows into Lake Mendocino, a major flood control reservoir. The river flows south from the lake through Mendocino to Sonoma County, paralleled by Highway 101. It turns west at Healdsburg, receiving water from Lake Sonoma via Dry Creek, and empties into the Pacific Ocean at Jenner.
rUssian rIVER ThuMb|gOaT RocK beacH AS vIEwed from The jEnNer CLIfFs lookinG souTh, ShoWing the mOutH Of the RUsSian River aT the PacifIc OcEan much of centRaL And northERn sonOma cOuNTY is In the waTErSHeD of ThE rUssIan RivEr And its tributariEs. the rIver rIseS iN tHe CoAsTal mouNtaiNs of MEndOcINO COuntY, NOrTh oF the cITy oF ukIah, anD FlOws into laKe MenDoCiNo, a MajoR floOD contrOl rEservoir. the RiVer flOWs souTh FrOm tHE lakE thRough mEndoCino to SOnoma CounTy, Paralleled by highWay 101. it tUrns WEst at hEaldSburg, reCEiVinG wATer froM lakE sonOma Via drY cREek, and EmptIeS into the pacIfic oCean aT jenNEr.