Siobhan is a distinctive girls' name in United States, ranking #1272 in 1997 with 139 recorded births. This places Siobhan in the top 8% of ranked US girls' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 1997 with 139 births ranking #1272. In 1997, approximately 1 in every 12,523 girls born was named Siobhan. FALLING Recent data shows the name is currently falling.