Rhiannon is a moderately popular girls' name in England & Wales, ranking #121 in 2002 with 382 recorded births. The name reached its all-time peak in 1998 with 657 births ranking #83. Since 1996, the popularity has decreased by 41.6%. In 2002, approximately 1 in every 700 girls born was named Rhiannon. STABLE Recent data shows the name is currently stable.