36 C.F.R. § 12.7 – Headstones and markers.

(a) Government headstones and markers authorized to be furnished at government expense are provided in accordance with NPS Policy and VA Policy.
(b) The erection of a marker or monument at private expense to mark a grave in lieu of a government headstone or marker is allowed only in certain national cemetery sections in which private headstones and markers were authorized as of January 1, 1947, and only with the prior approval of the Director. The name of the person(s) responsible for the purchase and erection of the private headstone or marker may not appear on the headstone or marker or be identified elsewhere in the cemetery as the donor(s) of the private headstone or marker.
(c) A person who requests authorization to erect a private headstone or marker shall provide the following information:
1. (1) A list of the names of each person to be inscribed upon the private headstone or marker;
2. (2) The written approval of the next-of-kin and the person who directed the burial of each person whose name is to be inscribed; and
3. (3) A scale plan depicting the details of design, materials, finish, carving, lettering and arrangement of the inscription and the foundation of the proposed private headstone or marker.
(d) The Director's approval of a request is conditioned upon the applicant's granting to the National Park Service the substantive right to remove and dispose of the private headstone or marker if, after it is installed, the applicant fails to maintain the private headstone or marker in a condition specified by the Director.
(e) When a private headstone or marker has been erected at a veteran's grave in a national cemetery, and the next-of-kin desires to inscribe thereon the name and appropriate data pertaining to an eligible family member of the deceased whose remains will not be interred, such inscription may be accomplished with the prior approval of the superintendent. Appropriate commemorative data may be inscribed when space permits. The words “In Memoriam” or “In Memory Of” are mandatory elements of such an inscription.
(f) Except as may be authorized by the Director or by Federal statutory law for making a group burial, the erection of a mausoleum, an overground vault or a headstone or marker determined by the superintendent not to be in keeping with the historic character of the national cemetery is prohibited. An underground vault may be placed at the time of interment at no expense to the National Park Service.