Rhiannon is a moderately popular girls' name in United States, ranking #497 in 2001 with 553 recorded births. The name reached its all-time peak in 1999 with 651 births ranking #424. Since 1996, the popularity has increased by 86.2%. In 2001, approximately 1 in every 3,256 girls born was named Rhiannon. STABLE Recent data shows the name is currently stable.