Unknown is a distinctive girls' name in United States, ranking #3733 in 2020 with 40 recorded births. The name reached its all-time peak in 2009 with 84 births ranking #2334. Since 1996, the popularity has decreased by 24.5%. In 2020, approximately 1 in every 40,388 girls born was named Unknown. STABLE Recent data shows the name is currently stable.