This is a worldwide study of Rasco/Roscoe and related surnames: Rasco, Rascoe, Rosco, Roscoe, Rascow, Roscow, Rusco, & Ruscoe.

“The simpler Anglicized versions of the name may have a foundation in Sixteenth Century Huguenot migrations to England by families named Rouscoue or Rauscoue...

DUTCH/FLEMISH ROOTS?

Author, critic and teacher Burton Rascoe in 1937 quoted a family historian, Harvey Dann, who believed the Huguenot Rascoes to be of Flemish or Dutch Flemish origin before establishing themselves in England... Dann found the earliest record of the name in England to be John Rouscoue (i), alien, in Herts in 1545. 

POSSIBLE DALMATION ORIGINS

Other research suggests the name may have Fourteenth Century origins on the Dalmatian Coast near Austria and Slovenia-Croatia... may have been Rascovich (or son of Rasco)...

HISPANIC CONNECTIONS

Occasionally one hears of a family named Rasco of sure and traceable Hispanic origins in this hemisphere and other parts of the world. Such families may add validity to the theories mentioned above about a Spanish stop over for members of the family who originated in the Dalmation region...  In Italy, Rasco and Bosco families have been found. ...

LAST STOP PROBABLY ENGLAND

Regardless of where in Europe the name originated, the only records located thus far indicate the family was in England for a number of decades before coming to the Colonies in the 1600s.

Where it has been possible to trace a branch of the family or one of its roots back to Europe, there is a conformity to the classic migration patterns of history. The Rusco family of Massachusetts came from East Anglia, England as did their Puritan neighbors...

Most of the neighbors and in-laws of our [USA] Rasco forefathers of Virginia and the Carolinas, whose European roots we can trace, came from the Southern Counties of England. An exception to this is the William Roscow family which came to Virginia from Lancashire in the Northwest section between Wales and Scotland in the 1600s...

AFRICAN-AMERICAN RASCOS

Rascos with an African-American heritage can be found in some areas of this country [USA]...”

Rasco, William E., and James Ray Rasco. The Rasco Family Tree, Roots, and Branches: The Descendants of Rachel Harrell and William Rasco (ca. 1750-1806) and Their Eight Children: A Family History. Knoxville, TN (P.O. Box 52527, Knoxville 37950-2527): Tennessee Valley Pub., 1994. Print.

Occurrences of the surname Rasco/Roscoe in the Guild Indexes

Modern Newspaper Index ........................... Roscoe 2, Ruscoe 1

Marriages of the World search .................... Rasco 1, Roscoe 4, Roscow 1, Ruscoe

The Guild Marriage Index ......................... Roscoe 46, Roscow 15, Ruscoe 27

Guild Probate Index .............................. Roscoe 5, Roscow 1

Worldwide Marriage Index ......................... Roscoe 10, Roscow 1, Ruscoe 2

The Guild BMD Vault .............................. Roscoe 96, Roscow 26, Ruscoe 15

Read more at https://one-name.org/results/#jec8lQZBbMAPdzYe.99

1)Identifying the different Y-DNA branches of the Rasco surname (a son to father study)

2)Using autosomal atDNA to find recent ancestor connections (a cousins study)

https://www.familytreedna.com/groups/rasco-roscoe/about

For Rasco/Roscoe Links [link no longer accessible]