Unknown is a distinctive girls' name in United States, ranking #6155 in 1997 with 16 recorded births. The name reached its all-time peak in 2009 with 84 births ranking #2334. Since 1996, the popularity has decreased by 69.8%. In 1997, approximately 1 in every 108,791 girls born was named Unknown. STABLE Recent data shows the name is currently stable.