What are the SSN prefixes for Illinois?

Illinois was assigned the area-number range 318-361. A Social Security number issued there before 2011 begins with one of these three-digit numbers.

Does an SSN starting with 318 mean the person is from Illinois?

For cards issued before June 25, 2011, an SSN whose first three digits fall in Illinois's range was issued in Illinois, usually based on the mailing address on the application, not necessarily birthplace. Numbers issued after randomization carry no location meaning.

How can I check a specific number?

Use the SSN checker to enter a full number and see whether its structure is valid, which state it maps to, and a rough estimate of when it was issued.

Social Security Number Prefixes for Illinois

Area numbers 318-361

area range: 1
lowest area number: 318
highest area number: 361
area numbers: 44

Illinois was assigned the Social Security area-number range 318-361. Before SSA randomized number assignment in June 2011, any SSN beginning with one of these three-digit prefixes was issued in Illinois, generally based on the mailing address on the application. Newer numbers are assigned randomly and no longer indicate a state.

Illinois area-number ranges

Area-number range	Count
318-361	44

Sample Illinois SSN patterns

Estimated issue years for the lowest area/group combinations (illustrative):

Pattern	Estimated issued	Status
318-01-####	1936-1950	Valid
318-03-####	1936-1950	Valid
318-05-####	1936-1950	Valid
318-07-####	1936-1950	Valid
318-09-####	1936-1950	Valid
318-10-####	1936-1950	Valid
318-12-####	1936-1950	Valid
318-14-####	1936-1950	Valid
318-16-####	1936-1950	Valid
318-18-####	1936-1950	Valid
318-20-####	1936-1950	Valid
318-22-####	1938-1951	Valid
318-24-####	1940-1952	Valid
318-26-####	1942-1954	Valid
318-28-####	1944-1955	Valid
318-30-####	1946-1957	Valid
318-32-####	1948-1958	Valid
318-34-####	1950-1959	Valid
318-36-####	1952-1961	Valid
318-38-####	1954-1962	Valid
318-40-####	1956-1963	Valid
318-42-####	1958-1965	Valid
318-44-####	1960-1966	Valid
318-46-####	1962-1968	Valid

Frequently asked questions

What are the SSN prefixes for Illinois?: Illinois was assigned the area-number range 318-361. A Social Security number issued there before 2011 begins with one of these three-digit numbers.
Does an SSN starting with 318 mean the person is from Illinois?: For cards issued before June 25, 2011, an SSN whose first three digits fall in Illinois's range was issued in Illinois, usually based on the mailing address on the application, not necessarily birthplace. Numbers issued after randomization carry no location meaning.
How can I check a specific number?: Use the SSN checker to enter a full number and see whether its structure is valid, which state it maps to, and a rough estimate of when it was issued.

Check a specific number with the SSN checker, or see all states.