Iowa Code § 461A.14: Reversion of gift.

If the lands transferred to the state as a gift, or if lands purchased in whole or in part by the state from moneys given for that purpose, shall be abandoned or sold and not used for state park purposes, the donor shall reclaim the land or funds donated by filing the donor’s request in writing with the executive council within six months of the time of the abandonment or sale by the state of such lands, but no interest or other charge shall be demanded of or paid by the state. Any unclaimed funds shall be used for park purposes.