A widow who is caring for children 16 years and younger will receive social security benefits based on her spouse's work earnings. The widow's benefits, however, will end when the youngest of the children reaches 16 years old. So the minimum years depends on the age of the youngest child. Moreover, the widow must remain unmarried to continue receiving the benefits during this time period.
A widow who is of retirement age can also receive her spouse's benefits starting at age 60, unmarried or remarried after age 60.
social security site
Widow Ebook Index