Iain is a distinctive boys' name in United States, ranking #1218 in 2002 with 113 recorded births. The name reached its all-time peak in 2003 with 126 births ranking #1181. Since 1996, the popularity has increased by 31.4%. In 2002, approximately 1 in every 17,181 boys born was named Iain. FALLING Recent data shows the name is currently falling.