The New England Historical And Genealogical Register featured Certificates of Headrights in the County Court of Lower Norfolk, Virginia, here and here (and perhaps elsewhere).
This is what was said about headrights at the FamilySearch Wiki:
Headright grants were issued from about 1618 to 1732. A person was given a patent for a certain number of acres (usually 50 per person) for himself, his wife, servants, slaves, or any other passengers for whom he provided passage.
A detailed explanation here.