September 21st - September 27th
National Singles Week was started in 1984 as a way to appreciate the growing ranks of unmarried people. Today, two out of three single people have never wed. It is estimated that there are 82 million single and unmarried adults in the United States. National Singles Week is celebrated the third full week in September (Sunday through Saturday).
Source: www.celebratelove.com/singlesweek.htm