Napa is the county seat of Napa County, California. It is the principal city of the Napa county Metropolitan Statistical Area, which encompasses Napa county. As of the 2000 census, the city had a total population of 72,585. The area was settled in the 1830s. It was incorporated as a city in 1872.

On December 31, 2005, the Napa River overflowed and flooded the entire downtown area and thousands of acres all over Napa County. More than 4,000 residents were evacuated and 1,000 homes were flooded or destroyed. The flood of 12/31/05 was the 23rd serious flood on the Napa River on record since 1865.