A Social Security Number (SSN) is a unique nine-digit identifier assigned to individuals in the United States. It was created in 1936 to track earnings and determine eligibility for Social Security benefits. Today, SSNs are used for various purposes, including tax reporting, credit applications, and identity verification. Each SSN is issued by the Social Security Administration (SSA) and is essential for accessing government services and benefits. It is important to protect your SSN to prevent identity theft, as unauthorized use can lead to financial fraud and other legal issues.