Unknown is a distinctive girls' name in United States, ranking #2623 in 2013 with 68 recorded births. The name reached its all-time peak in 2009 with 84 births ranking #2334. Since 1996, the popularity has increased by 28.3%. In 2013, approximately 1 in every 25,800 girls born was named Unknown. STABLE Recent data shows the name is currently stable.