Membership is open to eligible persons eighteen years of age or older, who are in support of the Constitution of the United States and the Order's Constitution and Bylaws.
There are two options of equal eligibility by lineal descent: (1) the applicant is lineally descended from Ancient Welsh Kings and Princes of Deheubarth, Gwent, Glamorgan Gwynedd, and Powys prior to December 11, 1282, the date of death of Llywelyn ap Gruffydd, also known as Llywelyn the Last, or (2) a Welsh immigrant prior to July 4, 1776.
Members who are verified by both eligibilities are recognized with the Dual Birthright Medal. These two lineal lines of descent need not be the same line.