It's in Northern California at the northeastern tip of San Francisco Bay (actuallycalled San Pablo Bay up that far), about an hour's drive north of San Francisco.
To the west is the Sonoma Valley , to the east is Lake Berryessa and Yolo and Solano Counties, and to the north Lake County. Napa Valley is actually just one of many valleys in Napa County, but it's by far the largest and best known. The valley itself is about 30 miles long and ranges from one to five miles wide.

Napa County has a population of about 110,000 people, and five incorporated cities. North to south, they are: Calistoga, St. Helena, Yountville, Napa and, at the southern end, American Canyon. Angwin, Deer Park, Lake Berryessa, Rutherford and Oakville are communities with post offices but aren't actual towns.

The county's primary industries are winegrape growing, wine production and tourism. Thanks to stringent and ongoing efforts by the vast majority of the voters, there is little development in the county itself; most commercial and residential development is in the cities. This preserves a huge amount of agricultural land, allowing Napa County to avoid the urban sprawl that has affected almost all other San Francisco Bay Area counties. The result is an attractive place for residents to live and tourists to visit.

The original inhabitants of the valley were the Wappo. The name Wappo was given by the Spanish and probably derived from the Spanish word "guapo", meaning "handsome." The natives were here at least 4,000 years before the Spaniards arrived. In 1831 there were an estimated 10,000 to 12,000 living in the valley . Most later lost their lives to cholera and smallpox, as well as to attacks by white men. There are still surviving Wappos in Napa , Sonoma and Lake counties.

The first American settler in the Napa Valley was George Yount. He arrived in 1831, became friends with General Mariano Vallejo, and was given an 11,000 acre Mexican land grant. He built the first wooden structure in the county, a two-story Kentucky block house. He also planted the first grapevines in the Napa Valley . The vines were from Mexico; it was not until 1860 that the higher quality European winegrapes were introduced.

Today the Napa Valley is one of the most popular tourist attractions in California, and world renowned for its wines. The fame of its wineries is matched by the reputation of its restaurants. Combined with the beauty of the area, they provide a vacation holiday without equal anywhere in the country.