For the wine region, see Napa Valley AVA. Napa County is a county located north of San Pablo Bay in the northern portion of the U.S. state of California. As of the 2010 census, the population was 136,484. The county seat is the City of Napa. Napa County was one of the original counties of California, created in 1850 at the time of statehood.
Area code 412 is a Pennsylvania area code that covers Pittsburgh and some of the surrounding areas. Area code 412 overlays the area code of 878. Pennsylvania has area codes of 215, 267, 272, 412, 484, 570, 610, 717, 724, 814, 878.
Summary. Until 1997, Pennsylvania had four area codes â 814, 412, 717 and 215. With the increased use of cell phones and consumers purchasing additional lines in their homes, the demand for additional telephone lines exploded.17 region-The 717 area codes stretches from Lancaster to Harrisburg, to York and Fulton County. Western Pennsylvania. 412, 724 and 878 region-The 412 area code is primarily located in Pittsburgh and 724 covers the suburbs of Pittsburgh.