The first digit of a SIN indicates the province in which it was registered:
<DL><DD>1: Atlantic Provinces: Nova Scotia, New Brunswick, Prince Edward Island, and Newfoundland and Labrador</DD><DD>2: Quebec</DD><DD>3: Quebec</DD><DD>4: Ontario (including overseas forces)</DD><DD>5: Ontario</DD><DD>6: Prairie Provinces (Manitoba, Saskatchewan, and Alberta), Northwest Territories, and Nunavut</DD><DD>7: Pacific Region (British Columbia and Yukon)</DD><DD>8: Not used</DD><DD>9: Temporary resident</DD><DD>0: Not used (Canada Revenue may assign fictitious SIN numbers beginning with zero to taxpayers who do not have SINs)</DD></DL>Note: While the first digit usually identifies the location of registration, the government has found it necessary in the past to supply certain regions with SIN numbers assigned to other regions.