| 600 | Special telecommunications needs in CanadaMore information at: Area Code 600 Phone Number Blocks |
| 601 | Mississippi (Jackson, Meridian, Natchez, McComb, Hattiesburg and central Mississippi, overlays with 769)More information at: Area Code 601 Phone Number Blocks |
| 602 | Arizona (Central Phoenix only)More information at: Area Code 602 Phone Number Blocks |
| 603 | New Hampshire (all)More information at: Area Code 603 Phone Number Blocks |
| 604 | British Columbia (Greater Vancouver Regional District and Abbotsford overlay with 778. Whistler, Chilliwack and remaining portion of 604 not part of overlay complex). The whole area, along with area code 250 will overlay with area code 778 in 2008More information at: Area Code 604 Phone Number Blocks |
| 605 | South Dakota (all)More information at: Area Code 605 Phone Number Blocks |
| 606 | Kentucky (Ashland, Hazard, Somerset, London, Corbin, Pikeville, Maysville and eastern Kentucky)More information at: Area Code 606 Phone Number Blocks |
| 607 | New York (Binghamton, Elmira, Bath, Norwich, Oneonta, Ithaca, and south central New York)More information at: Area Code 607 Phone Number Blocks |
| 608 | Wisconsin (Madison, La Crosse, Platteville, Beloit and southwestern Wisconsin)More information at: Area Code 608 Phone Number Blocks |
| 609 | New Jersey (Atlantic City, Brown Mills, Trenton, and central & southeastern New Jersey)More information at: Area Code 609 Phone Number Blocks |
| 610 | Pennsylvania (Reading, Chester and southeastern Pennsylvania, overlays with 484 and 835)More information at: Area Code 610 Phone Number Blocks |
| 611 | Repair ServiceMore information at: Area Code 611 Phone Number Blocks |
| 612 | Minnesota (Central Minneapolis, Fort Snelling, St Anthony and Richfield)More information at: Area Code 612 Phone Number Blocks |
| 613 | Ontario (Ottawa, eastern and southeastern Ontario)More information at: Area Code 613 Phone Number Blocks |
| 614 | Ohio (Columbus area)More information at: Area Code 614 Phone Number Blocks |
| 615 | Tennessee (Nashville, Murfreesboro, Springfield, Lebanon, Dickson and north central Tennessee), split from 901 in 1954.More information at: Area Code 615 Phone Number Blocks |
| 616 | Michigan (Grand Rapids, Holland, Greenville, Grand Haven, Zeeland, Ionia and southwestern Michigan)More information at: Area Code 616 Phone Number Blocks |
| 617 | Massachusetts (Boston, Cambridge, east central Massachusetts and close-in Boston suburbs, overlays with 857)More information at: Area Code 617 Phone Number Blocks |
| 618 | Illinois (Alton, Belleville, Carbondale, Centralia, Mount Vernon and southern Illinois)More information at: Area Code 618 Phone Number Blocks |
| 619 | California (Southern and eastern suburbs and southern portion of the city of San Diego) Former area code for areas now covered by 858 and 760More information at: Area Code 619 Phone Number Blocks |
| 620 | Kansas (Dodge City, Great Bend, Parsons, Liberal and southern Kansas not including the Wichita metropolitan area)More information at: Area Code 620 Phone Number Blocks |
| 623 | Arizona (Glendale, Buckeye, Peoria, western Phoenix area and western Phoenix suburbs only)More information at: Area Code 623 Phone Number Blocks |
| 626 | California (Arcadia, Temple City, Covina, Pasadena and eastern Los Angeles suburbs)More information at: Area Code 626 Phone Number Blocks |
| 627 | California This Area code is scheduled to provide numbering relief to Area code 707 but no date has been assigned for this to go into effect.More information at: Area Code 627 Phone Number Blocks |
| 628 | California This Area code is scheduled to provide numbering relief to Area code 415 but no date has been assigned for this to go into effect.More information at: Area Code 628 Phone Number Blocks |
| 630 | Illinois (Aurora, Naperville, and other Western Chicago suburbs, overlays with 331)More information at: Area Code 630 Phone Number Blocks |
| 631 | New York (Suffolk County)-had previously been under 516.More information at: Area Code 631 Phone Number Blocks |
| 636 | Missouri (St. Charles, Chesterfield, Union, De Soto, Troy and east central Missouri)More information at: Area Code 636 Phone Number Blocks |
| 641 | Iowa (Mason City, Oskaloosa, Creston, Pella, Ottumwa, Britt, Clear Lake, Fairfield and central Iowa)More information at: Area Code 641 Phone Number Blocks |
| 646 | New York (New York City: Manhattan only; cell phone overlays with 212 and 917)More information at: Area Code 646 Phone Number Blocks |
| 647 | Ontario (Toronto; overlays with 416)More information at: Area Code 647 Phone Number Blocks |
| 649 | the Turks and Caicos Islands, split from Area code 809. (all)More information at: Area Code 649 Phone Number Blocks |
| 650 | California (San Mateo, Palo Alto, Redwood City, Menlo Park, Mountain View and southern San Francisco suburbs)More information at: Area Code 650 Phone Number Blocks |
| 651 | Minnesota (St Paul, Lindstrom, Red Wing, Hastings and east central Minnesota)More information at: Area Code 651 Phone Number Blocks |
| 657 | California This Area code is scheduled to provide numbering relief to Area code 714 with a planned in service date of September 23, 2008.More information at: Area Code 657 Phone Number Blocks |
| 659 | Alabama This Area code is scheduled to provide numbering relief to Area code 205 but no date has been assigned for this to go into effect.More information at: Area Code 659 Phone Number Blocks |
| 660 | Missouri (Marshall, Sedalia, Macon, Trenton, Maryville, Bethany and north central Missouri)More information at: Area Code 660 Phone Number Blocks |
| 661 | California (Bakersfield, Mojave, Santa Clarita, Palmdale and south central California)More information at: Area Code 661 Phone Number Blocks |
| 662 | Mississippi (Greenville, Tupelo, Winona, Columbus, Holly Springs and northern Mississippi)More information at: Area Code 662 Phone Number Blocks |
| 664 | Montserrat, split from 809. (all)More information at: Area Code 664 Phone Number Blocks |
| 667 | Maryland This Area code is scheduled to provide numbering relief to Area code 443 but no date has been assigned for this to go into effect.More information at: Area Code 667 Phone Number Blocks |
| 669 | California This Area code is scheduled to provide numbering relief to Area code 408 but no date has been assigned for this to go into effect.More information at: Area Code 669 Phone Number Blocks |
| 670 | Northern Marianas (former country code for this territory of the United States)More information at: Area Code 670 Phone Number Blocks |
| 671 | Guam (former country code for this territory of the United States)More information at: Area Code 671 Phone Number Blocks |
| 678 | Georgia (all of metro Atlanta, overlays both 404 and 770 and in the future 470)More information at: Area Code 678 Phone Number Blocks |
| 679 | Michigan This Area code is scheduled to provide numbering relief to Area code 313 but no date has been assigned for this to go into effect.More information at: Area Code 679 Phone Number Blocks |
| 681 | West Virginia (taking full effect in 2009; overlay of 304)More information at: Area Code 681 Phone Number Blocks |
| 682 | Texas (Fort Worth, Arlington, Grandview, Weatherford, Rhome, overlays with 817)More information at: Area Code 682 Phone Number Blocks |
| 684 | American Samoa (former country code for this territory of the United States)More information at: Area Code 684 Phone Number Blocks |
| 689 | Florida This Area code is scheduled to provide numbering relief to Area code 407 but no date has been assigned for this to go into effect.More information at: Area Code 689 Phone Number Blocks |