Prior to 2001, all of northern Indiana had the "219" area code.

(WNDU) - Beginning Saturday, Apr. 24, everyone in northern Indiana’s 574 and 219 telephone area codes is encouraged to start using 10 digits, rather than seven, to make local phone calls. Local calls ...

Northwest Indiana's 219 area code, the basis for the 219 Day celebration annually held around Feb. 19 in Hammond, also apparently is a very lucky set of numbers for hundreds of Hoosier Lottery players ...