Back when I was a kid, most of northern California was in the 916 area code. In 1997, the area code was split so that the metro Sacramento area remained 916 and the outlying areas became 530. Starting in the next few days (February 10th), a new area code will be overlaid on top of the area currently served by 916. Thus folks in Sacramento will be required to dial both area code and seven digit number—even for local calls. The new area code is 279.
Further Reading