Rhiannon is a distinctive girls' name in United States, ranking #1754 in 2015 with 120 recorded births. The name reached its all-time peak in 1999 with 651 births ranking #424. Since 1996, the popularity has decreased by 59.6%. In 2015, approximately 1 in every 14,872 girls born was named Rhiannon. STABLE Recent data shows the name is currently stable.