Ja is a distinctive boys' name in United States, ranking #6731 in 2002 with 10 recorded births. The name reached its all-time peak in 1999 with 20 births ranking #3751. Since 1996, the popularity has increased by 100.0%. In 2002, approximately 1 in every 194,147 boys born was named Ja. FALLING Recent data shows the name is currently falling.