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.
State: IL-Illinois. Active: True. Area codes 630 and 331 are coterminous area codes under the North American Numbering Plan in the United States that cover a portion of suburban Chicago, specifically most of Dupage County in Illinois.t is used in Yorkville, Illinois, as well, which is in southwest exurban Kendall County. On October 7, 2007, area code 331 overlaid the 630 and 11-digit dialing was implemented for those area codes. Previously, 630 split off from area code 708 in 1996, which itself split off from area code 312 in 1989.