SPRINGFIELD –With new telephone numbers in west-central Illinois in high demand, the Illinois Commerce Commission approved the new 861 area code to overlay the existing 309 area code region. The 309 area code serves parts of Bureau, Marshall and 18 other counties in the state. Customers in the 309 area code overlay region may be assigned a number in the new 861 area code when they request new service or an additional line. Existing telephone numbers will not change.
