This collection contains records of flood control projects in Sonoma County undertaken by the Sonoma County Flood Control and Water Conservation District in Forestville; Graton; Hyland Acres; Healdsburg; Petaluma; Santa Rosa; Occidental; Russian River; South Park; Spring Creek and Sonoma Valley.

This collection contains official records created or commissioned by the Sonoma County Board of Supervisors, including records of special districts in Sonoma County. Some records jointly created by the Sonoma County Administrator's Office.