Iain is a distinctive boys' name in United States, ranking #1429 in 1997 with 76 recorded births. The name reached its all-time peak in 2003 with 126 births ranking #1181. Since 1996, the popularity has decreased by 11.6%. In 1997, approximately 1 in every 24,804 boys born was named Iain. FALLING Recent data shows the name is currently falling.