Rhiannon is a moderately popular girls' name in England & Wales, ranking #113 in 2001 with 410 recorded births. The name reached its all-time peak in 1998 with 657 births ranking #83. Since 1996, the popularity has decreased by 37.3%. In 2001, approximately 1 in every 654 girls born was named Rhiannon. STABLE Recent data shows the name is currently stable.