Rhiannon is a moderately popular girls' name in England & Wales, ranking #164 in 2004 with 325 recorded births. The name reached its all-time peak in 1998 with 657 births ranking #83. Since 1996, the popularity has decreased by 50.3%. In 2004, approximately 1 in every 880 girls born was named Rhiannon. STABLE Recent data shows the name is currently stable.