The light green county indicated is County Cavan, Ireland. This is believed to be the location that the Riley ancestor's came from.
The names Riley and O'Reilly in Ireland are derived from the native Gaelic O'Raghaillaigh Sept that was based in Counties Cavan and Westmeath. These names are among the ten most frequently found in Ireland and although widespread can still be mostly found in the region of the ancestral homeland.
This Branch consisits of many surnames which include, but not limited to, Killenbeck, Hyde, Blackman, Niles, Place, Hileman, and Wiebenga.