Visitors to the National Archives here know they will find the Declaration of Independence, the Constitution and the Bill of Rights in the main building’s magnificent rotunda.
But they can no longer find the patent file for the Wright brothers’ flying machine or maps for the first atomic bomb missions in the archives inventory.
Many historical items the archives once possessed are missing, including Civil War telegrams from Abraham Lincoln, presidential portraits of Franklin D. Roosevelt, NASA photographs from space and the moon, and presidential pardons.
Some were stolen by researchers or archives employees. Others simply disappeared. And more than that is gone.
The archives’ inspector general, Paul Brachfeld, is conducting a criminal investigation into a missing hard drive with copies of records from the Clinton administration. Because the drive may also include classified information, Senator Charles E. Grassley, Republican of Iowa, calls its loss a major national security breach.
Mr. Brachfeld has documented thousands of electronic storage devices, including computers and servers, that have disappeared over the past decade.
Mr. Grassley, who has demanded an accounting of all missing items, said the loss of historical documents “is completely unacceptable.”
The archives’ stewardship of the nation’s records has been questioned before. In a well-publicized incident, former President Bill Clinton’s national security adviser, Samuel R. Berger, took documents in the fall of 2003 while preparing for testimony to the Sept. 11 commission. In September 2005, Mr. Berger was sentenced to two years of probation and 100 hours of community service, was fined $50,000 and lost his security clearance for three years.