Unknown is a distinctive girls' name in United States, ranking #2885 in 2008 with 62 recorded births. The name reached its all-time peak in 2009 with 84 births ranking #2334. Since 1996, the popularity has increased by 17.0%. In 2008, approximately 1 in every 30,495 girls born was named Unknown. STABLE Recent data shows the name is currently stable.