All assignees
798 prefixes in 312 · initial assignments from the NANPA CO code file, 09/17/2026
| NPA-NXX | Rate center | OCN | Assigned | Pooled |
|---|---|---|---|---|
| 312-901 | CHICGOZN01 | 6630 | — | — |
| 312-902 | CHICGOZN01 | 9329 | — | — |
| 312-903 | CHICGOZN01 | 9748 | 2001-04-13 | — |
| 312-904 | CHICGOZN01 | 9329 | — | — |
| 312-905 | CHICGOZN01 | 9329 | — | Yes |
| 312-906 | CHICGOZN01 | 9329 | — | Yes |
| 312-907 | CHICGOZN01 | 6529 | — | Yes |
| 312-908 | CHICGOZN01 | 9329 | — | — |
| 312-909 | CHICGOZN01 | 6333 | — | — |
| 312-910 | CHICGOZN01 | 224C | 2022-09-19 | Yes |
| 312-911 | XXXXXXXXXX | MULT | — | — |
| 312-912 | CHICGOZN01 | 9329 | — | Yes |
| 312-913 | CHICGOZN01 | 9329 | — | — |
| 312-914 | CHICGOZN01 | 6333 | — | — |
| 312-915 | CHICGOZN01 | 9329 | — | — |
| 312-917 | CHICGOZN01 | 9329 | — | — |
| 312-918 | CHICGOZN01 | 6529 | 2013-08-19 | Yes |
| 312-919 | CHICGOZN01 | 6333 | — | — |
| 312-920 | CHICGOZN01 | 9329 | — | — |
| 312-921 | CHICGOZN01 | 9329 | 2008-07-21 | Yes |
| 312-922 | CHICGOZN01 | 9329 | — | — |
| 312-923 | CHICGOZN01 | 9329 | — | — |
| 312-924 | CHICGOZN01 | 829J | — | — |
| 312-925 | CHICGOZN01 | 6534 | — | — |
| 312-926 | CHICGOZN01 | 9329 | — | — |
| 312-927 | CHICGOZN01 | 6529 | 2002-08-21 | — |
| 312-928 | CHICGOZN01 | 9329 | — | Yes |
| 312-929 | CHICGOZN01 | 6529 | 2006-04-27 | Yes |
| 312-930 | CHICGOZN01 | 9329 | — | — |
| 312-931 | CHICGOZN01 | 9329 | — | Yes |
| 312-932 | CHICGOZN01 | 9329 | — | Yes |
| 312-933 | CHICGOZN01 | 6529 | — | Yes |
| 312-934 | CHICGOZN01 | 6529 | 2014-12-08 | Yes |
| 312-935 | CHICGOZN01 | 9329 | — | — |
| 312-936 | CHICGOZN01 | 9329 | — | — |
| 312-937 | CHICGOZN01 | 6333 | 2014-09-25 | Yes |
| 312-938 | CHICGOZN01 | 9329 | — | — |
| 312-939 | CHICGOZN01 | 9329 | — | — |
| 312-940 | CHICGOZN01 | 063E | 2013-09-20 | Yes |
| 312-941 | CHICGOZN01 | 6630 | — | — |
| 312-942 | CHICGOZN01 | 9329 | — | — |
| 312-943 | CHICGOZN01 | 9329 | — | — |
| 312-944 | CHICGOZN01 | 9329 | — | — |
| 312-945 | CHICGOZN01 | 9329 | — | Yes |
| 312-946 | CHICGOZN01 | 9329 | — | — |
| 312-947 | CHICGOZN01 | 9329 | 2010-11-18 | Yes |
| 312-948 | CHICGOZN01 | 829J | 2001-04-10 | Yes |
| 312-949 | CHICGOZN01 | 9329 | — | — |
| 312-950 | — | — | ||
| 312-951 | CHICGOZN01 | 9329 | — | Yes |
| 312-952 | CHICGOZN01 | 6534 | — | — |
| 312-953 | CHICGOZN01 | 6534 | — | — |
| 312-954 | CHICGOZN01 | 9329 | — | — |
| 312-955 | CHICGOZN01 | 8702 | — | — |
| 312-956 | CHICGOZN01 | 6534 | 2014-09-29 | Yes |
| 312-957 | CHICGOZN01 | 9329 | — | Yes |
| 312-958 | — | — | ||
| 312-959 | — | — | ||
| 312-960 | CHICGOZN01 | 9329 | — | Yes |
| 312-961 | CHICGOZN01 | 6534 | — | — |
| 312-962 | CHICGOZN01 | 6115 | — | Yes |
| 312-963 | CHICGOZN01 | 6630 | — | — |
| 312-964 | CHICGOZN01 | 224C | — | Yes |
| 312-965 | CHICGOZN01 | 6333 | — | — |
| 312-966 | CHICGOZN01 | 5562 | 2014-11-18 | Yes |
| 312-967 | CHICGOZN01 | 984E | 2014-08-07 | Yes |
| 312-968 | LA GRANGE | 6333 | — | Yes |
| 312-969 | LA GRANGE | 6333 | — | Yes |
| 312-970 | CHICGOZN01 | 9329 | — | Yes |
| 312-971 | CHICGOZN01 | 984E | 2014-05-01 | Yes |
| 312-972 | CHICGOZN01 | 6534 | — | — |
| 312-973 | CHICGOZN01 | 7229 | 2014-02-19 | Yes |
| 312-974 | CHICGOZN01 | 9329 | — | — |
| 312-975 | CHICGOZN01 | 6529 | 2014-09-15 | Yes |
| 312-976 | — | — | ||
| 312-977 | CHICGOZN01 | 9329 | — | — |
| 312-978 | CHICGOZN01 | 6529 | 2013-10-22 | Yes |
| 312-979 | CHICGOZN01 | 9329 | — | — |
| 312-980 | CHICGOZN01 | 7136 | — | — |
| 312-981 | CHICGOZN01 | 829J | 2001-04-10 | Yes |
| 312-982 | CHICGOZN01 | 318J | 2014-10-07 | Yes |
| 312-983 | CHICGOZN01 | 9329 | — | Yes |
| 312-984 | CHICGOZN01 | 9329 | — | — |
| 312-985 | CHICGOZN01 | 829J | 2001-04-10 | Yes |
| 312-986 | CHICGOZN01 | 9329 | — | — |
| 312-987 | CHICGOZN01 | 9329 | — | — |
| 312-988 | CHICGOZN01 | 9329 | — | Yes |
| 312-989 | CHICGOZN01 | 6534 | 2015-06-25 | Yes |
| 312-990 | HINSDALE | 6534 | — | Yes |
| 312-991 | WHEELING | 6534 | — | Yes |
| 312-992 | CHICGOZN01 | 9329 | — | — |
| 312-993 | CHICGOZN01 | 9329 | — | Yes |
| 312-994 | CHICGOZN01 | 829J | 2001-04-10 | Yes |
| 312-995 | CHICGOZN01 | 7136 | 2014-08-12 | Yes |
| 312-996 | CHICGOZN01 | 9329 | — | — |
| 312-997 | CHICGOZN01 | 9329 | — | Yes |
| 312-998 | CHICGOZN01 | 508J | 2014-08-12 | Yes |
| 312-999 | CHICGOZN01 | 7229 | 2010-08-20 | Yes |
These are initial assignees from NANPA CO-code records — because of number portability, the current serving carrier of individual numbers may differ. Bulk export requires a membership.