NPA Codes in USA starting with 6
| NPA | Country | Time Difference (From GMT) | State | State Abbrv. | Service Date | Comments |
| 601 | USA | -6 | Mississippi | MS | | |
| 602 | USA | -7 | Arizona | AZ | | |
| 603 | USA | -5 | New Hampshire | NH | | |
| 605 | USA | -6 | South Dakota | SD | | |
| 606 | USA | -5 | Kentucky | KY | | |
| 607 | USA | -5 | New York | NY | | |
| 608 | USA | -6 | Wisconsin | WI | | |
| 609 | USA | -5 | New Jersey | NJ | | |
| 610 | USA | -5 | Pennsylvania | PA | 08 Jan 1994 | |
| 612 | USA | -6 | Minnesota | MN | | |
| 614 | USA | -5 | Ohio | OH | | |
| 615 | USA | -5 to -6 | Tennessee | TN | | |
| 616 | USA | -5 | Michigan | MI | | |
| 617 | USA | -5 | Massachusetts | MA | | |
| 618 | USA | -6 | Illinois | IL | | |
| 619 | USA | -8 | California | CA | | |
| 620 | USA | -6 | Kansas | KS | 03 Feb 2001 | |
| 623 | USA | -7 | Arizona | AZ | 01 Mar 1999 | |
| 626 | USA | -8 | California | CA | 14 Jun 1997 | |
| 628 | USA | -8 | California | CA | 16 Aug 2014 | |
| 629 | USA | -5 to -6 | Tennessee | TN | 26 Jul 2014 | |
| 630 | USA | -6 | Illinois | IL | 03 Aug 1996 | |
| 631 | USA | -5 | New York | NY | 01 Nov 1999 | |
| 636 | USA | -5 | Missouri | MO | 22 May 1999 | |
| 640 | USA | -5 | New Jersey | NJ | 17 Sep 2018 | |
| 641 | USA | -6 | Iowa | IA | 09 Jul 2000 | |
| 646 | USA | -5 | New York | NY | 01 Jul 1999 | |
| 650 | USA | -8 | California | CA | 02 Aug 1997 | |
| 651 | USA | -6 | Minnesota | MN | 12 Jul 1998 | |
| 657 | USA | -8 | California | CA | 23 Aug 2008 | |
| 659 | USA | -6 | Alabama | AL | | Proposed |
| 660 | USA | -5 | Missouri | MO | 12 Oct 1997 | |
| 661 | USA | -8 | California | CA | 13 Feb 1999 | |
| 662 | USA | -6 | Mississippi | MS | 19 Apr 1999 | |
| 667 | USA | -5 | Maryland | MD | 24 Mar 2012 | |
| 669 | USA | -8 | California | CA | 20 Nov 2012 | |
| 678 | USA | -5 | Georgia | GA | 01 Jun 1998 | |
| 679 | USA | -5 | Michigan | MI | | Proposed |
| 680 | USA | -5 | New York | NY | 11 Mar 2017 | |
| 681 | USA | -5 | West Virginia | WV | 26 Jul 2008 | |
| 682 | USA | -6 to -7 | Texas | TX | 07 Oct 2000 | |
| 689 | USA | -5 to -6 | Florida | FL | | Suspended |
See World Zone 1 for explanation of "NPA"
Where shown:
| Time Diff. |
is with respect to GMT (UCT) |
Suspended
Pending
Proposed |
indicate the code is not in use: the "Service Date" has been delayed or not set |
| Service Date |
is the date code becomes (or became) effective. If no date is shown, the code was introduced before 1995 |