Not Chicago, and proud of it
In Western Illinois, a 312 or 773 number can read as an outsider.
309 marks you as part of the region that stretches from Peoria on the Illinois River to Rock Island on the Mississippi. Businesses in Bloomington-Normal, farm towns and river cities have used it since 1957. Showing that prefix on caller ID tells customers you understand how things work downstate. It is a quiet way to earn a first conversation.