The English surname Riley comes from ‘Ryley’ in Lancashire, so named from Old English term ryge which meant ‘rye’. Added with that is the term leah which meant ‘wood’ or ‘clearing’. It is a very common surname in northern England.

In Ireland the surname is Reilly.

Most Riley families originated in Ireland and some from England.

In England the two major counties for Riley families are Lancashire and Yorkshire. and Midlowthian counties of Scotland have higher numbers of Richards families.

The states within the United States having many Riley families are Ohio, , New York, Pennsylvania and Illinois.

In the 1880s most Riley families were farmers.

Famous: Billie Lee Riley (, record producer and singer), Gina Riley (Australian actor, writer, singer and comedian), Jack Riley (Irish ice hockey player), Charles O. L. Riley (first Anglican Archbishop of Perth, Australia), Arthur Riley (South African footballer), Bob Riley (founder of race car company Riley & Scott), Jennie C. Riley (American country and gospel music singer), Ruth Riley (professional basketball player for the Women‘s National Basketball Association), Wayne Riley (Australian golfer), Harold Riley (English artist) and Ivan Riley (1924 American Olympic athlete in 400 meter hurdles).