Illinois area codes — detailed data
Working detail for Illinois's 17 area codes: history, capacity forecasts and dialing plans, straight from NANPA's NPA database.
Aggregate footprint: the state's 17 geographic codes currently carry 8,917 active NXX prefixes over 1,432 rate-center anchorings, with 6,415 prefixes in thousands-block pooling. 15 of the codes serve territory inside FCC top-100 metropolitan statistical areas.
Lineage: 224 came out of 847 in 2002; 331 came out of 630 in 2007; 447 came out of 217 in 2021; 464 came out of 708 in 2022; 630 came out of 708 in 1996; 708 came out of 312 in 1989; 730 came out of 618 in 2023; 773 came out of 312 in 1996; 779 came out of 815 in 2007; 847 came out of 708 in 1996; 861 came out of 309 in 2023; 872 came out of 312 in 2009. The remaining codes (217, 309, 312, 618, 815) date back to the plan's early assignments.
Dialing plans: 6 codes use plain ten-digit local dialing (10D); 11 require 1+ ten digits. Overlay territories always dial ten digits; the 2021 988-hotline transition moved most others to ten digits as well.
The tightest capacity in the state is 224 (complex 224/847), projected to exhaust 3Q 2033.
Status: no Illinois code is currently in jeopardy or active relief planning — capacity is adequate near-term per NANPA.
Code-by-code notes
217 — spawned 447; overlaid by 447; exhaust forecast 2Q 2046.
618 — spawned 730; overlaid by 730; exhaust forecast 4Q 2040.
815 — spawned 779; overlaid by 779; exhaust forecast 1Q 2044.
312 — spawned 708, 773, 872; overlaid by 872; exhaust forecast 1Q 2049.
773 — carved from 312; overlaid by 872; exhaust forecast 4Q 2046.
847 — spawned 224; carved from 708; overlaid by 224; exhaust forecast 3Q 2033.
630 — spawned 331; carved from 708; overlaid by 331; exhaust forecast 1Q 2080.
708 — spawned 847, 630, 464; carved from 312; overlaid by 464; exhaust forecast 2Q 2053.
309 — spawned 861; overlaid by 861; exhaust forecast 4Q 2102.
224 — carved from 847; overlaid by 847; exhaust forecast 3Q 2033.
| Code | In service | Split from | Exhaust (NANPA) | Local dialing | Status |
|---|---|---|---|---|---|
| 217 | 1947-01-01 | — | 2Q 2046 | 10D | Normal |
| 224 | 2002-01-05 | 847 | 3Q 2033 | 1+10D | Normal |
| 309 | 1957-01-01 | — | 4Q 2102 | 10D | Normal |
| 312 | 1947-01-01 | — | 1Q 2049 | 1+10D | Normal |
| 331 | 2007-10-07 | 630 | 1Q 2080 | 1+10D | Normal |
| 447 | 2021-03-27 | 217 | 2Q 2046 | 10D | Normal |
| 464 | 2022-01-21 | 708 | 2Q 2053 | 1+10D | Normal |
| 618 | 1947-01-01 | — | 4Q 2040 | 10D | Normal |
| 630 | 1996-08-03 | 708 | 1Q 2080 | 1+10D | Normal |
| 708 | 1989-11-11 | 312 | 2Q 2053 | 1+10D | Normal |
| 730 | 2023-07-07 | 618 | 4Q 2040 | 10D | Normal |
| 773 | 1996-10-12 | 312 | 4Q 2046 | 1+10D | Normal |
| 779 | 2007-03-17 | 815 | 1Q 2044 | 1+10D | Normal |
| 815 | 1947-01-01 | — | 1Q 2044 | 1+10D | Normal |
| 847 | 1996-01-20 | 708 | 3Q 2033 | 1+10D | Normal |
| 861 | 2023-02-24 | 309 | 4Q 2102 | 10D | Normal |
| 872 | 2009-11-07 | 312 | 4Q 2046 | 1+10D | Normal |