Many of the older Gregg Families of Dallas and Cass County, MO came from Ross County, OH. The Ross County Greggs came from the Quaker Greggs, Timmons and Hadley of PA and DE in early 1700s. The orgins of Greggs are from Scotland via Ireland. The orgins of Timmons are from Ireland and the orgins of Hadley's are from England via Ireland.
Some unconfirmed researchers have Greggs traced to Iain Dhee MacGregor (b. 1370, Scotland; d. 1415, Scotland).