Rhiannon is a moderately popular girls' name in United States, ranking #453 in 2000 with 612 recorded births. The name reached its all-time peak in 1999 with 651 births ranking #424. Since 1996, the popularity has increased by 106.1%. In 2000, approximately 1 in every 2,967 girls born was named Rhiannon. STABLE Recent data shows the name is currently stable.