Located in the Eastern (GMT -05:00) time zone. Area code 443 serves the state of Maryland. This area code was assigned on June 21st, 1996. On June 1st, 1997 it went into service. 443 is a General Purpose Code. 443 service area does overlap with 410 667 area codes. Dialing pattern for local calls within the same NPA (area code) is 10D.