Milly is a distinctive girls' name in United States, ranking #4979 in 1999 with 22 recorded births. This places Milly in the top 29% of ranked US girls' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 2014 with 129 births ranking #1657. Since 1996, the popularity has increased by 100.0%. In 1999, approximately 1 in every 80,626 girls born was named Milly. STABLE Recent data shows the name is currently stable.