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.
Area code 256 serves the northern portion of Alabama, including the Huntsville and Decatur metropolitan areas. There are plans to overlay a new area code, 938, in the year 2011. As a result, 10-digit dialing will be mandatory beginning in 2010.ajor cities like Decatur within area code 256 are also listed on this page. More area codes, including those outside of Alabama, are found on the AreaCode.org homepage. Some telephone area codes are overlaid, requiring 10-digit dialing.