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.
If this is for a UK phone number totalling eleven digits long, then  it's probably a London phone number, as the area code  020 is for London. (The '31' would be the first  â¦ digits of the eight-figure local number.)    There are also other countries that have domestic telephone area  codes like 02031 or similar.n the UK, area code 0141 is Glasgow.    Other countries may have a domestic telephone area code 01412 or  similar.    If 00 is your international access prefix â¦ , then 00 1 412 is a call  to +1 412, which is Pittsburgh, Pennsylvania, USA.