Unknown is a distinctive girls' name in United States, ranking #2644 in 2018 with 66 recorded births. The name reached its all-time peak in 2009 with 84 births ranking #2334. Since 1996, the popularity has increased by 24.5%. In 2018, approximately 1 in every 25,764 girls born was named Unknown. STABLE Recent data shows the name is currently stable.