Jamestown was a failed English settlement in the Continental U.S.A. Plymouth Rock (1620) was a success. Geographically, North America is a continent from Canada to Panama, and includes most of the Caribbean Islands, thus there were dozens of successful European (Spanish) settlements by 1620 on that continent.
The first failed "European" settlement in part of mainland North America (Continental U.S.) was attempted in Florida by Ponce de Leon in (1521), although it was discovered in 1513 by the same explorer. In 1528, Porfilo de Narvaez, with 600 men and 80 horses also failed to settle the peninsula, and Saint Augustine (1570) is the first successful settlement in the U.S.
Old Spanish maps of Florida extended the peninsula up to Delaware Bay and the Mississippi River (Rio Espiritu Santo).
In 1526, the town of San Miguel de Gualdape (today in Georgia), was founded by Lucas Vazquez de Ayllon, the first settlement in Continental U.S.A. This settlement had many homes, a church, three priests, and about 600 men, women and children. A harsh winter forced many to disperse throughout Georgia and South Carolina, others were rescued by the local Indians. The survivors, mostly men, intermarried with the natives. After abandoning the town, only 150 returned to Hispaniola.
Maybe that's why the English settlers, over 100 years later, were amazed to find native Indians with Caucasian features in that area?