The area code 730 is located in Alton, Illinois.
Area code 730 serves Alton, Illinois and the wider Metro East region of the St. Louis area as an overlay to the long-standing 618 area code. Alton sits on the Mississippi River in Madison County, known for river bluffs and the scenic Great River Road. The 730 overlay entered service on July 7, 2023, adding new number supply without changing existing 618 numbers. It keeps the same geographic footprint as 618, so local callers now use 10‑digit dialing for all calls.
730/618 covers Alton and many nearby communities, including:
In and around Alton, notable landmarks include the Clark Bridge, the Piasa Bird site, and the Meeting of the Great Rivers Scenic Byway near the Mississippi–Illinois Rivers confluence. The overlay means customers keep their current numbers; new phone lines may receive a 730 number while using the same calling area and services. The region observes Central Time, which helps businesses and residents align with the greater St. Louis market. Interesting trivia: 730 overlays 618, one of the original North American area codes created in 1947.
“Area code 730 will overlay area code 618 … effective July 7, 2023.” — North American Numbering Plan Administrator (NANPA)