Rhiannon is a distinctive girls' name in United States, ranking #1048 in 2008 with 250 recorded births. The name reached its all-time peak in 1999 with 651 births ranking #424. Since 1996, the popularity has decreased by 15.8%. In 2008, approximately 1 in every 7,563 girls born was named Rhiannon. STABLE Recent data shows the name is currently stable.