Ukiah Valley is a valley located in Mendocino County, California, United States. It contains the Mendocino County seat of Ukiah. It also is home to the unincorporated towns of Redwood Valley, Calpella, Potter Valley and Talmage. Lake Mendocino and the headwaters of the Russian River are located in the greater Ukiah valley.
While part of the greater Ukiah area, Willits is located to the north of the Ukiah Valley in Little Lake Valley, part of the Eel River drainage basin.
Linguistically, "Ukiah Valley" is redundant: "Ukiah" comes from words in the language of the Pomo people meaning "south valley".