Unknown is a distinctive girls' name in United States, ranking #2767 in 2012 with 64 recorded births. The name reached its all-time peak in 2009 with 84 births ranking #2334. Since 1996, the popularity has increased by 20.8%. In 2012, approximately 1 in every 27,512 girls born was named Unknown. STABLE Recent data shows the name is currently stable.