Napa County was established in 1850 and is one of the original 27 counties and is named after the Napa Indians who once inhabited the area. Napa County is the center of the state's wine industry.

Napa County is located in the North Bay Area, 50 miles north of San Francisco. Contiguous counties include Solano, Sonoma, Lake and Yolo. The land area of the County is approximately 756 square miles. It is located in the Governor's Office of Emergency Services Coastal Region and Mutual Aid Region II. It extends from the Napa River Delta on the south and west to the Mayacmas Mountain range in the north.

Napa County has a long, rich history in grape growing, with the first vines planted in the 1840's. The Valley currently has 232 wineries, producing more than 6 million cases of wines totaling over $1 billion dollars in sales. The wine industry in Napa accounts for $4 billion of California's annual $33 billion economic impact from winemaking and related industries. Wine is California's number one finished agricultural product and the third highest valued agricultural commodity exported from California.