Delaware Code
Subchapter I. Appointment, Bond and Tenure of Guardian
§ 3909. Term of guardianship.

(a) If the only allegation of disability in the petition for appointment of a guardian was that the person was a minor, unless terminated earlier by the Court upon application of the guardian, the minor or other interested party, or by the death of the minor, the guardianship of such minor shall terminate automatically when the minor attains the age of 18 years.
(b) The automatic termination of the guardianship of the property of any minor shall not relieve the guardian of any duty to account. The guardian may be released by the Court of Chancery upon application of the guardian or the former minor.
(c) The guardianship of the person or property, or both, of any person with a disability for reasons other than minority shall continue until 1 of the following occur:

(1) The death of the person with a disability.
(2) Termination by the Court of Chancery upon application of the guardian, the person with a disability, or another interested party.