The National Archives, accessible through Archives.gov, has a searchable database of military records, photographs and documents. Although not all of the National Archives' holdings are available online, the website reports that it has information dating all the way back to the American Revolutionary War available upon request.
The National Archives contains military records that date back to the birth of the United States and others that are as recent as the Vietnam War. The database contains information such as casualty records, awards and distinctions, combat information, enlistment and draft records, and photographs. If a person is unable to find the desired information or records through the National Archives, he is able to request it elsewhere on the Archives.gov website.
The National Archives contains thousands of documents with a wide array of military records. Anyone looking for military photographs from the American Civil War or World War II is able to access the photographs directly from the archives. For information related to other wars, it is sometimes necessary to make a special request.
The National Archives is the official repository of records for the U.S. Air Force, Army, Marine Corps, Navy and Coast Guard. The National Archives website contains a number of tips for where to get started when searching for specific documents.