Unknown is a distinctive girls' name in United States, ranking #4411 in 2003 with 30 recorded births. The name reached its all-time peak in 2009 with 84 births ranking #2334. Since 1996, the popularity has decreased by 43.4%. In 2003, approximately 1 in every 60,902 girls born was named Unknown. STABLE Recent data shows the name is currently stable.