For Thyroglossal Cyst Most Common site is
Suprahyoid
Subhyoid
Foreman caecum
At Thyroid Isthmus
Although Thyroglossal Duct cysts may occur anywhere from the Base of the tongue to the thyroid gland , most are found at or just below the hyoid bone. Source : Sabiston 20th edition Pg : 1862
Endocrinology and breast