Iain is a distinctive boys' name in United States, ranking #3268 in 2017 with 35 recorded births. The name reached its all-time peak in 2003 with 126 births ranking #1181. Since 1996, the popularity has decreased by 59.3%. In 2017, approximately 1 in every 52,866 boys born was named Iain. FALLING Recent data shows the name is currently falling.