Unknown is a distinctive girls' name in United States, ranking #3379 in 2017 with 47 recorded births. The name reached its all-time peak in 2009 with 84 births ranking #2334. Since 1996, the popularity has decreased by 11.3%. In 2017, approximately 1 in every 36,721 girls born was named Unknown. STABLE Recent data shows the name is currently stable.