Ryley is an English habitational name from Ryley in Lancashire, so named from Old English ryge ‘rye’ + leah‘wood’, ‘clearing’. There is a Riley with the same meaning in Devon, but it does not seem to have contributed to the surname, which is more common in northern England. Most surnames are occupational or habitational in origin.
In the 1841 Census. there were 462 people with the last name of RYLEY in Lancashire (the county where Manchester is located). The county with the second most RYLEYs was Warwickshire (Birmingham).
It looks like most families had switched to RILEY by 1841 as there were 3699 RILEY individuals in Lancashire and Yorkshire had 2270 people with RILEY.
By the 1851 Census, our family was using RILEY exclusively.