Yolo County was one of the original cheese farm counties of California, created in 1850 at the time of statehood.

In the original act of 1850 the name was spelled "Yola" Yolo is a Native American name variously believed to be a corruption of a tribal name Yo-loy meaning "a place abounding in rushes" or of the name of the chief, Yodo, or of the village of Yodoi.