A county commission may designate areas of special or unique interest, with sites, buildings and structures within those areas, which are of local, regional, statewide or national significance.  An area that has been so designated does not limit the use of nor require any alteration of any privately owned property in the area for any purpose. The commission may also publish a register setting forth information concerning those areas; place markers on private property only with the consent of the property owners; place markers on public property and along highways or streets designating those  areas; seek and accept gifts, bequests, endowments and funds to accomplish the purpose of this section; sell, lease or alter property it owns in or near the designated areas; seek the advice and assistance of individuals, groups and departments and governmental agencies; and seek codesignation of areas with a municipality where an area is to be designated in each jurisdiction.