The National Historic Preservation Act of 1966 established a national historic preservation program to provide for the ongoing identification and protection of historic properties. An historic property is any building, structure, object, site, or district listed on or eligible for inclusion in the National Register of Historic Places. To be eligible for the National Register, a property must meet one of the following criteria: (1) be associated with historic events or activities, (2) be associated with important people, (3) embody distinctive design or physical characteristics, or (4) have potential to provide important information about prehistory or history. In addition, the property generally has to be 50 years of age or older. The act generally requires federal agencies to identify, evaluate, and nominate historic properties under agency control to the National Register of Historic Places. The Office of the Deputy Under Secretary of Defense for Environmental Security implements the act within DOD and requires each military service to designate federal preservation officers to coordinate its historic property program. As part of the program, the services require each installation to prepare an integrated cultural resources management plan that should include an inventory of all known historic properties as well as an evaluation of properties that may be eligible for listing on the National Register. Once an installation completes its evaluation, it coordinates its recommendation with the State Historic Preservation Officer. If the state disagrees with the installation’s recommendation, the decision can be elevated to the National Park Service. The military services maintain information on historic properties such as year acquired, square footage, and current use in their real property databases. The act also requires that federal agencies (1) consider the effects of any maintenance, repair, or renovation on historic properties—both those on the National Register, as well as those eligible to be placed on the register, and (2) consult with the State Historic Preservation Officer to attempt to reach an agreement regarding actions that affect historic properties that is beneficial to all. Thus, when installation officials are about to begin work on a property either on or eligible for inclusion on the National Register, they should consult with the state about what work will be accomplished and what materials will be used; however, responsibility for funding the work remains with the Department of Defense. Each of the military services has reported backlogs of facilities maintenance and repair work in recent years, regardless of whether a property is historic or nonhistoric. Although the military services maintain cultural resource records on historical properties and also real property databases, containing both historical and nonhistorical properties, they do not have complete and reliable data on the number of historic properties. None of the services have a centralized database that identifies all of their respective historic properties. Our analysis of data from the military services’ real property databases and cultural resource records indicates the services have about 17,300 historic properties, most of which are in-use. However, results of military service auditor tests of additions, deletions, and modification transactions for fiscal year 1999 indicated that real property transactions were not promptly recorded. These problems, along with issues we identified such as conflicting information between the Army’s real property database and its cultural resource records, and the lack of information on Navy and Air Force properties that are eligible for listing, raise questions regarding the reliability of the services’ information. Further, while there is a large number of properties that need to be evaluated over the next 10 years, it is uncertain how many of these properties will meet criteria and become eligible for listing on the National Register. Although each service maintains a real property database that should indicate whether individual buildings and structures are historic properties, our work has shown that these databases are not reliable. For example, the Navy, Marine Corps, and Air Force systems only identify properties listed on the National Register, not other properties that are eligible for listing on the National Register. While the Army database includes both listed and eligible properties, it does not include all properties identified as historic in the cultural resource records. At the same time, questions exist regarding the accuracy and completeness of cultural resource records. The number of historic properties in table 1 represents our analysis of the services’ real property databases and cultural resource records. While information included in table 1 provides the best available data on the number of historic properties, it is subject to certain limitations. The following examples highlight the problems we had in determining the number of historic properties within each service. The Army’s real property database identifies 6,189 properties and its cultural resource records, maintained at each installation, indicate 8,593 properties as historic—excluding buildings approved for demolition. Our comparison of information between the real property database and cultural resource records indicates the Army has 10,110 historic properties. Army officials stated that the additional properties included in the cultural resource records represent properties that are eligible for listing, but installations have not updated the real property database. For example, the cultural resource records identified 1,790 historic properties at Hawthorne Army Depot, Nevada, which were not identified as historic in the Army’s real property database. About 1,533 of these historic properties are munitions storage structures. While a cultural resources official with the Army believes that the cultural resource records are more accurate than the database, he also has concerns about the accuracy of these records. For example, the cultural resource records indicate that there are 15 historic properties within the Military District of Washington. According to the real property database, there are 576 historic properties within the District. The Navy’s real property database identifies 1,283 historic properties, but our work indicates the Navy has at least 2,526 such properties. The real property database does not identify 855 historic properties included in the Pearl Harbor, Hawaii historic district. In addition, the database does not identify 295 family housing dwellings at various locations, 64 properties at Naval Shipyard Portsmouth, Maine, nor 32 properties at the Naval Academy, Maryland, as historic properties, eligible for listing on the National Register. The cultural resource office does not maintain records on properties eligible for listing on the register, so we could not determine how many properties might be eligible throughout the Navy. In addition, the facilities database identifies 66 properties built after 1950 as historic— 14 at the Naval Training Center Great Lakes, Illinois, and 11 at the U. S. Naval Academy, Maryland. However, cultural resource officials at both installations stated that none of these properties are historic. The remaining 41 properties are at locations we did not visit. The Marine Corps uses the same real property database as the Navy and it does not identify properties that are eligible for listing on the register. Our analysis of available cultural resource records at Marine Corps headquarters indicates there are 590 properties eligible for listing, including 239 at the Marine Corps Combat Development Center, Quantico, Virginia, and 210 at Marine Corps Base Camp Lejeune, North Carolina. The Air Force’s cultural resource records indicate that there are 1,831 properties listed on the National Register. However, our analysis of the cultural resource data indicates that there are 1,691 properties on the National Register. The difference occurs because the Air Force included (1) properties owned by the Army, (2) nonhistoric properties at some installations, and (3) properties that had been demolished. The Air Force cultural resource records also identify 2,346 eligible properties; however, the cultural resource office could not identify where 1,183 of these properties were located. An Air Force cultural resource official stated that the number of eligible properties was developed from a 1999 inquiry— telephone and e-mail responses—but no supporting documentation was retained. The remaining 1,163 eligible properties are family housing that the Air Force can identify by base. Service officials stated they are aware of the inconsistencies in the number of historic properties between the real property databases and the cultural resource records. Army officials in the Office of the Assistant Chief of Staff for Installation Management stated that they are working to reconcile the inconsistencies. The Navy cultural resource manager agreed that the existing real property database does not accurately capture data on historic properties. He also acknowledged that the database does not distinguish between properties that are listed on the National Register and those determined to be eligible for listing and whether properties are part of a historic district or listed individually. However, he stated that the Navy is updating its real property database to allow it to make these distinctions. Cultural resource officials in each of the service headquarters stated, and our own observations confirmed, that the majority of the historic properties are being used. About 36 percent of all historic properties are family housing dwellings. There were a relatively small number of vacant buildings at some of the installations we visited. In some cases, the installations were developing plans to lease these properties to the private sector. At the installations we visited, 87, or about 4 percent, of the identified 2,395 historic properties were vacant. In some cases, the buildings were vacant because the base did not have sufficient funds to make the buildings usable and/or the structures were no longer needed for mission requirements. For example, 2 of the identified 65 historic properties at the Naval Training Center, Great Lakes, were vacant because, according to the installation’s Director of Public Works, funds were not available to repair and update the property for administrative office space. At Portsmouth Naval Shipyard, Maine, there is no mission requirement for the naval prison structure there that has been closed since 1974. Navy officials at Portsmouth are trying to lease the prison building and six other historic properties to the private sector. Other locations are also developing plans to lease vacant buildings, including 40 historic buildings at Fort Sam Houston, Texas. Further, properties that were no longer needed to meet mission requirements and had lost their historical significance or structural integrity were demolished by each of the services. In fact, seven of the nine installations we visited had demolished or reached an agreement with their respective state preservation office to demolish certain historic properties. For example, officials at Fort Bliss, Texas, stated they have an agreement to demolish 24 historic properties as long as other historic properties are maintained. Likewise, 5 of the 107 original historic properties have been demolished at Scott Air Base, Illinois.