Located in the Central (GMT -06:00) time zone. Area code 630 serves the state of Illinois. This area code was assigned on August 9th, 1994. On August 3rd, 1996 it went into service. 630 is a General Purpose Code. 630 service area does overlap with 331 area codes. Dialing pattern for local calls within the same NPA (area code) is 1+10D.