Decoding Social Security Numbers in One Step
(for numbers issued prior to June 25, 2011)


Stephen P. Morse, San Francisco





Three-Digit Decoder

SSN starting with - XX - XXXX
was issued in
Where card was issued, not where person was born




Five-Digit Decoder

SSN starting with - - XXXX
was issued in 001-01: New Hampshire, 1936-1950
Where and when card was issued, not where and when person was born




Three-Digit Assignment Chart

0xx, 1xx 2xx, 3xx 4xx 5xx 5xx 6xx 7xx 8xx, 9xx
001-003 NH 212-220 MD 400-407 KY 501-502 ND 540-544 OR 600-601 AZ 700-728 RR* 800-899 XX*
004-007 ME 221-222 DE 408-415 TN 503-504 SD 545-573 CA 602-626 CA 729-733 EE* 900-999 ITIN*
008-009 VT 223-231 VA 416-424 AL 505-508 NE 574-574 AK 627-645 TX 734-749 XX*
010-034 MA 232-232 NW* 425-428 MS 509-515 KS 575-576 HI 646-647 UT 750-751 HI
035-039 RI 233-236 WV 429-432 AR 516-517 MT 577-579 DC 648-649 NM 752-755 MS
040-049 CT 237-246 NC 433-439 LA 518-519 ID 580-580 VI 650-653 CO 756-763 TN
050-134 NY 247-251 SC 440-448 OK 520-520 WY 581-584 PR 654-658 SC 764-765 AZ
135-158 NJ 252-260 GA 449-467 TX 521-524 CO 585-585 NM 659-665 LA 766-772 FL
159-211 PA 261-267 FL 468-477 MN 525-525 NM 586-586 PI* 666-666 XX* 773-799 XX*
268-302 OH 478-485 IA 526-527 AZ 587-588 MS 667-675 GA
303-317 IN 486-500 MO 528-529 UT 589-595 FL 676-679 AR
318-361 IL 530-530 NV 596-599 PR 680-680 NV
362-386 MI 531-539 WA 681-690 NC
387-399 WI 691-699 VA


NW* = North Carolina if next two digits are 30, otherwise West Virginia
PI* = Pacific Islands (Guam, American Samoa, Northern Mariana Islands, Philipines)
RR* = Railroad Workers (prior to July 1, 1963)
EE* = Enumeration at Entry
ITIN* = Individual Taxpayer Identification Number if next two digits are in range 70-88
XX* = Unassigned



The structure of Social Security Numbers can be found in Jerry Crow and Barbara Bennett's article .
Later number assignments can be found at the Social Security Administration website
The structure of Individual Taxpayer Identification Numbers can be found on the Internal Revue Service website .
This page was automatically updated monthly through June 2011. Since then it has been static.

Stephen P. Morse, 2007