Morrows in the American South
Almost all American Morrows with Southern roots at some point come across research suggesting they are descended from David Morrow of Lower Norfolk Co, VA. David Morrow is shown on a land patent deed with headright Richard Whitehurst on 22 Nov 1651, indicating his immigration from Norfolk, England.
The vast majority of those lines are untrue. The Morrow DNA Project has proven that descendants from many of these various lines are not related to each other, or as it goes in DNA parlance, they share no common male ancestor in the last several thousand years.
[ Many families now designated with the surname Morrow, are in fact actually Murrays. Murray is pronounced as Morrah - Morroh- Morrow in the Scottish lowlands; evidence via yDNA research has proven that a large number of males in both the Morrow DNA project & the Murray DNA project, are definitely descended in different lines, from the same common ancestors; generally Scottish males named Murray. Often-times these males were resident in Ulster- Northern Ireland at some point in time.]
There is one subgroup of Southern Morrows that are believed to descend from David Morrow above. David named his son Alexander in his 1792 will. Two men, David b. ~1690 and Daniel b. ~1708, who were born in Virginia and are believed to be sons of Alexander have descendants in the DNA project. DNA results for those descendants indicate they are related to each other, and they have a common ancestor in the last 400 years. See the link above for more information on how the DNA, combined with paper research, suggests they are related.
On a more general note, almost all Morrow families carry a story that their ancestor is Irish, Scotch Irish, or occasionally, English. Early colonial families concentrated in North and South Carolina, and branched out primarily to Alabama, Georgia, Mississippi, Texas, Arkansas, and Missouri by the late 1800s. The numerous Morrows that immigrated first to New York or Pennsylvania stayed out of those Southern states almost entirely, moving west to Ohio, Illinois and Iowa.